Coronavirus Reinfection / 2nd Wave Infection

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trader32176
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Re: Coronavirus Reinfection / 2nd Wave Infection

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COVID research updates: The immune trait that could allow viral reinfection

02 October 2020


Nature wades through the literature on the new coronavirus — and summarizes key papers as they appear.

https://www.nature.com/articles/d41586-020-00502-w

The immune trait that could allow viral reinfection

Waning antibody levels or a poorly developed immune response to SARS-CoV-2 could put people at risk of reinfection, one case suggests.

In March, a care-home resident in their sixties developed severe pneumonia and tested positive for the new coronavirus. The individual spent more than one month in hospital before testing negative. In July, the individual tested positive again, with milder symptoms of coughing and shortness of breath.

Genomic analysis by Jason Goldman at the University of Washington, Seattle, and his colleagues (J. D. Goldman et al. Preprint at medRxiv https://doi.org/fbvj; 2020) showed that these were two separate infection events. The team also found that after the second infection, the individual produced only low levels of antibodies, and that these decreased over time. The person might have had a similar response to the first infection, which could explain why the individual was not protected against the second infection, the authors say.

The team also measured the individual’s neutralizing antibodies, which protect cells against infection. The person had lower levels of these potent antibodies against the version of SARS-CoV-2 that caused the first infection than against the version that caused the second infection.

The researchers say that these measurements provide a useful benchmark for antibody levels that do not protect against reinfection. The research has not yet been peer reviewed.
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Re: Coronavirus Reinfection / 2nd Wave Infection

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Scientists are reporting several cases of Covid-19 reinfection — but the implications are complicated

August 28, 2020

https://www.statnews.com/2020/08/28/cov ... lications/

Following the news this week of what appears to have been the first confirmed case of a Covid-19 reinfection, other researchers have been coming forward with their own reports. One in Belgium, another in the Netherlands. And now, one in Nevada.

What caught experts’ attention about the case of the 25-year-old Reno man was not that he appears to have contracted SARS-CoV-2 (the name of the virus that causes Covid-19) a second time. Rather, it’s that his second bout was more serious than his first.

Immunologists had expected that if the immune response generated after an initial infection could not prevent a second case, then it should at least stave off more severe illness. That’s what occurred with the first known reinfection case, in a 33-year-old Hong Kong man.

Still, despite what happened to the man in Nevada, researchers are stressing this is not a sky-is-falling situation or one that should result in firm conclusions. They always presumed people would become vulnerable to Covid-19 again some time after recovering from an initial case, based on how our immune systems respond to other respiratory viruses, including other coronaviruses. It’s possible that these early cases of reinfection are outliers and have features that won’t apply to the tens of millions of other people who have already shaken off Covid-19.

“There are millions and millions of cases,” said Michael Mina, an epidemiologist at Harvard’s T.H. Chan School of Public Health. The real question that should get the most focus, Mina said, is, “What happens to most people?”

But with more reinfection reports likely to make it into the scientific literature soon, and from there into the mainstream press, here are some things to look for in assessing them.

What’s the deal with the Nevada case?


The Reno resident in question first tested positive for SARS-CoV-2 in April after coming down with a sore throat, cough, and headache, as well as nausea and diarrhea. He got better over time and later tested negative twice.

But then, some 48 days later, the man started experiencing headaches, cough, and other symptoms again. Eventually, he became so sick that he had to be hospitalized and was found to have pneumonia.

Researchers sequenced virus samples from both of his infections and found they were different, providing evidence that this was a new infection distinct from the first.

What happens when we get Covid-19 in the first case?

Researchers are finding that, generally, people who get Covid-19 develop a healthy immune response replete with both antibodies (molecules that can block pathogens from infecting cells) and T cells (which help wipe out the virus). This is what happens after other viral infections.

In addition to fending off the virus the first time, that immune response also creates memories of the virus, should it try to invade a second time. It’s thought, then, that people who recover from Covid-19 will typically be protected from another case for some amount of time. With other coronaviruses, protection is thought to last for perhaps a little less than a year to about three years.

But researchers can’t tell how long immunity will last with a new pathogen (like SARS-CoV-2) until people start getting reinfected. They also don’t know exactly what mechanisms provide protection against Covid-19, nor do they know what levels of antibodies or T cells are required to signal that someone is protected through a blood test. (These are called the “correlates of protection.”)

Why do experts expect second cases to be milder?

With other viruses, protective immunity doesn’t just vanish one day. Instead, it wanes over time. Researchers have then hypothesized that with SARS-CoV-2, perhaps our immune systems might not always be able to prevent it from getting a toehold in our cells — to halt infection entirely — but that it could still put up enough of a fight to guard us from getting really sick. Again, this is what happens with other respiratory pathogens.

And it’s why some researchers actually looked at the Hong Kong case with relief. The man had mild to moderate Covid-19 symptoms during the first case, but was asymptomatic the second time. It was a demonstration, experts said, of what you would want your immune system to do. (The case was only detected because the man’s sample was taken at the airport when he arrived back in Hong Kong after traveling in Europe.)

“The fact that somebody may get reinfected is not surprising,” Malik Peiris, a virologist at the University of Hong Kong, told STAT earlier this week about the first reinfection. “But the reinfection didn’t cause disease, so that’s the first point.”

The Nevada case, then, provides a counterexample to that.

What kind of immune response did the person who was reinfected generate initially?

Earlier, we described the robust immune response that most people who have Covid-19 seem to mount. But that was a generalization. Infections and the immune responses they induce in different people are “heterogeneous,” said Sarah Cobey, an epidemiologist and evolutionary biologist at the University of Chicago.

Older people often generate weaker immune responses than younger people. Some studies have also indicated that milder cases of Covid-19 induce tamer immune responses that might not provide as lasting or as thorough of a defense as stronger immune responses. The man in Hong Kong, for example, did not generate antibodies to the virus after his first infection, at least to the level that could be detected by blood tests. Perhaps that explains why he contracted the virus again just about 4 1/2 months after recovering from his initial infection.

In the Nevada case, researchers did not test what kind of immune response the man generated after the first case.

“Infection is not some binary event,” Cobey said. And with reinfection, “there’s going to be some viral replication, but the question is how much is the immune system getting engaged?”

What might be broadly meaningful is when people who mounted robust immune responses start getting reinfected, and how severe their second cases are.

Are people who have Covid-19 a second time infectious?

As discussed, immune memory can prevent reinfection. If it can’t, it might stave off serious illness. But there’s a third aspect of this, too.

“The most important question for reinfection, with the most serious implications for controlling the pandemic, is whether reinfected people can transmit the virus to others,” Columbia University virologist Angela Rasmussen wrote in Slate this week.

Unfortunately, neither the Hong Kong nor the Reno studies looked at this question. But if most people who get reinfected don’t spread the virus, that’s obviously good news.

What happens when people broadly become susceptible again?


Whether it’s six months after the first infection or nine months or a year or longer, at some point, protection for most people who recover from Covid-19 is expected to wane. And without the arrival of a vaccine and broad uptake of it, that could change the dynamics of local outbreaks.

In some communities, it’s thought that more than 20% of residents have experienced an initial Covid-19 case, and are thus theoretically protected from another case for some time. That is still below the point of herd immunity — when enough people are immune that transmission doesn’t occur — but still, the fewer vulnerable people there are, the less likely spread is to occur.

On the flip side though, if more people become susceptible to the virus again, that could increase the risk of transmission. Modelers are starting to factor that possibility into their forecasts.

A crucial question for which there is not an answer yet is whether what happened to the man in Reno, where the second case was more severe than the first, remains a rare occurrence, as researchers expect and hope. As the Nevada researchers wrote, “the generalizability of this finding is unknown.”
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Re: Coronavirus Reinfection / 2nd Wave Infection

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35-year study hints that coronavirus immunity doesn't last long

10/1/20


https://www.livescience.com/seasonal-co ... ction.html

Coronaviruses that cause the common cold can infect people repeatedly, hinting that immunity to the novel coronavirus that causes COVID-19 might be similarly short-lived.

In a new study, published Sept. 14 in the journal Nature Medicine, scientists monitored 10 individuals for more than 35 years to determine how often they became infected with the four known seasonal coronaviruses. Since these viruses — known as HCoV-NL63, HCoV-229E, HCoV-OC43 and HCoV-HKU1 — either cause mild symptoms of the common cold or no symptoms at all, the team periodically screened the participants' blood for antibodies to spot new cases of infection.

When blood samples show an increase in the number of antibodies targeting a specific virus, as compared with prior samples, that means that the person's immune system is fighting off a new infection. The researchers determined how steep this shift in antibody levels had to be to constitute a confirmed infection, rather than random fluctuation.

"The new data show that immunity to other coronaviruses tends to be short-lived, with reinfections happening quite often about 12 months later and, in some cases, even sooner
," Dr. Francis Collins, director of the National Institutes of Health (NIH), wrote in a commentary about the research. In a few instances, reinfections occurred as early as six months and nine months after a prior infection, the study authors found.

The 10 study participants were all part of the Amsterdam Cohort Studies (ACS) on HIV-1 infection and AIDS, a study of the prevalence, incidence and risk factors for HIV infection that began in the 1980s. The participants, all HIV-negative, gave blood samples every three to six months throughout the study, providing 513 samples in total.

For the new study the authors rescreened those samples for coronavirus infections, in particular looking for antibodies that target a specific portion of each virus's nucleocapsid — the hard shell of protein that surrounds their genetic material, known as RNA.

Based on this analysis, the team found that each participant caught three to 17 coronavirus infections within the study period, with reinfections occurring every six months to eight years and nine months. Most often, however, reinfection of a particular coronavirus occurred about a year after the prior infection.

"We show that reinfections by natural infection occur for all four seasonal coronaviruses, suggesting that it is a common feature for all human coronaviruses, including SARS-CoV-2," the virus that causes COVID-19, the authors wrote.

Although the authors did not study SARS-CoV-2 in their research, they argue that the trend seen among common coronaviruses might still extend to the new virus. All the common coronaviruses, despite belonging to the same family, are genetically and biologically distinct, so any traits shared among them may be "representative of all human coronaviruses, including SARS-CoV-2," the authors wrote. That said, we don't yet know whether SARS-CoV-2 has the potential to reinfect humans as often as the others do.

What's more, "at least three caveats ought to be kept in mind when interpreting these data," Collins noted.

First, the participants' fluctuating antibody levels don't tell us anything about whether they actually got sick with each reinfection. The increase in antibodies "might have provided exactly the response needed to convert a significant respiratory illness to a mild case of the sniffles or no illness at all," Collins wrote. In theory, it's also possible the four viruses may have had genetic mutations that allowed them to reinfect people. And participants may have had some immunity to the viruses through their white blood cells, rather than their antibodies alone.

White blood cells known as B cells and T cells work together to recognize foreign substances in the body, including viruses, and rally the immune system to fight pathogens in a variety of ways, Live Science previously reported. "Antibodies are only one marker for immunity, which is probably also influenced by B cell- and T cell-mediated immunity," the authors noted.

T cells and B cells may also contribute to immunity against SARS-CoV-2, though we don't know how much, Collins wrote. As people gain immunity to the virus, either through natural infections or a future vaccine, it will be important to track how long that immunity lasts, he said. It's possible that people will need to be vaccinated on a recurring basis to keep the virus at bay, Live Science previously reported.

In the new study, the team also found that seasonal coronavirus infections occur more often in the winter months than summer months in the Netherlands, and suggested that COVID-19 may eventually share the same seasonal pattern. Other experts have also predicted that COVID-19 may circulate annually after the pandemic ends.
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Re: Coronavirus Reinfection / 2nd Wave Infection

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Fake Wave of False Positives

10/6/20

(There are many different opinions on some of these topics . I try to post the latest info on these topics for info reasons only)

https://rclutz.wordpress.com/2020/10/06 ... positives/

Dr. Mike Yeadon, a former Vice President and Chief Science Officer for Pfizer for 16 years, says that half or even “almost all” of tests for COVID are false positives. Dr. Yeadon also argues that the threshold for herd immunity may be much lower than previously thought, and may have been reached in many countries already.

In an interview last week Dr. Yeadon was asked: “we are basing a government policy, an economic policy, a civil liberties policy, in terms of limiting people to six people in a meeting…all based on, what may well be, completely fake data on this coronavirus?” Dr. Yeadon answered with a simple “yes.”

Dr. Yeadon said in the interview that, given the “shape” of all important indicators in a worldwide pandemic, such as hospitalizations, ICU utilization, and deaths, “the pandemic is fundamentally over.”

“Were it not for the test data that you get from the TV all the time, you would rightly conclude that the pandemic was over, as nothing much has happened. Of course people go to the hospital, moving into the autumn flu season…but there is no science to suggest a second wave should happen.”

Dr. Mike Yeadon on new paper:


I never expected to be writing something like this. I am an ordinary person, recently semi-retired from a career in the pharmaceutical industry and biotech, where I spent over 30 years trying to solve problems of disease understanding and seek new treatments for allergic and inflammatory disorders of lung and skin. I’ve always been interested in problem solving, so when anything biological comes along, my attention is drawn to it. Come 2020, came SARS-CoV-2. I’ve written about the pandemic as objectively as I could. The scientific method never leaves a person who trained and worked as a professional scientist. Please do read that piece. My co-authors & I will submit it to the normal rigours of peer review, but that process is slow and many pieces of new science this year have come to attention through pre-print servers and other less conventional outlets.

Executive Summary

Evidence presented in this paper indicates that the severe acute respiratory syndrome coronavirus 2 pandemic as an event in the UK is essentially complete, with ongoing and anticipated challenges well within the capacity of a normalised NHS to cope. The virus infection has passed through the bulk of the population as a result of wholly natural processes and evidence indicates that in the UK and other heavily infected European countries the spread of the virus has been all but halted by a substantial reduction in the susceptible population. This has occurred because the level of infection required to introduce enough immunity into the population to reduce the reproduction number (R) permanently below 1 occurred at markedly lower infection rates and loss of life than had been initially anticipated. The evidence presented in this paper indicates that there should be no expectation of a large scale ‘second wave’ with smaller localised outbreaks when the virus contacts pockets of previously uninfected populations.

Current mass testing using the PCR test is inappropriate in its current form. If it is to continue, then results and reporting should be refined to meet the gold standard of testing methodology to give clinicians improved information so that they are able to make appropriate clinical decisions. Positive tests should be confirmed by testing a second sample and all positive tests should be reported along with the Cycle Threshold (Ct) obtained during the test to aid assessment of a patient’s viral load.

It is recommended that a greater focus be placed on evidence-based medicine rather than highly sensitive theoretical modelling based on assumptions and unknowns. Current evidence allows for a greatly improved understanding of positive infectious patients and using the evidence to improve measurements and understanding can lead to sensitive measurements of active cases to give a more accurate warning of escalating cases and potential issues and outbreaks.

It is important to recall what it is that the PCR test measures, and it is simply the presence of partial RNA sequences present in the intact virus. This means that even a true positive does not necessarily indicate the presence of viable virus. In limited studies to date, many researchers have shown that some subjects remain PCR-positive long after the ability to culture virus from swabs has disappeared. We term this a ‘cold positive’ (to distinguish it from a ‘hot positive’, someone actually infected with intact virus). The key point about ‘cold positives’ is that they are not ill, not symptomatic, not going to become symptomatic and, furthermore, are unable to infect others. As each PCR test that is carried out returns the Cycle Threshold (Ct) used to obtain a positive result, it is important that this Ct is reported with every positive result. The Ct gives strong evidence of the viral load and aids clinicians in determining if a patient has a “hot” infectious positive result or a “cold” non-infectious positive result. Gniazdowski et al (2020) studied 161 positive PCR test samples with a Ct value below 23 that yielded 91.5% of virus isolates and the study showed a strong correlation between recovery of SARS-CoV-2 infectious virus on cell culture and Ct values. Ct values above 30 returned negative cultures in all except one case.

Note that recent so-called ’spikes’ were never accompanied or followed by people getting ill, going to hospital and dying in elevated numbers. Consequently, it is possible that most of the positives from mass testing are either false positives or ‘cold positives’ (fragments of real virus which are not intact and incapable of replication or of causing disease or infecting others) and therefore begs the question of whether mass testing of patients without symptoms is in fact helpful or misleading? It may be of relevance to note that, on August 24th the US CDC changed its guidance on when PCR testing is appropriate. They now recommend not testing people with no symptoms who are not contacts in a contact-tracing activity.

Read the linked paper for full description of the supporting evidence and analysis. Reprinted below is are remarks from Dr. Mina that I found accessible explaining the issue.

Background from previous post On Non-Infectious Covid Positives

Daniel Payne writes at Just the News : Growing research indicates many COVID-19 cases might not be infectious at all.

Elevated ‘cycle thresholds’ may be detecting virus long after it is past the point of infection.

A growing body of research suggests that a significant number of confirmed COVID-19 infections in the U.S. — perhaps as many as 9 out of every 10 — may not be infectious at all, with much of the country’s testing equipment possibly picking up mere fragments of the disease rather than full-blown infections.

Yet a burgeoning line of scientific inquiry suggests that many confirmed infections of COVID-19 may actually be just residual traces of the virus itself, a contention that — if true — may suggest both that current high levels of positive viruses are clinically insignificant and that the mitigation measures used to suppress them may be excessive.

The former chief scientific advisor of Pfizer has told talkRADIO he does not believe there is a second wave, and has challenged the Government to prove otherwise.

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Re: Coronavirus Reinfection / 2nd Wave Infection

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New age and sex-specific model of COVID-19 transmission

10/11/20


https://www.news-medical.net/news/20201 ... ssion.aspx


Researchers at the University of Rostock in Germany have developed a model of coronavirus disease 2019 (COVID-19) transmission that considers subdivisions of age and sex to provide better insights into the impact that increased contact rates might have on the risk of infection and mortality.

Study authors Achim Doerre and Gabriele Doblhammer say that under the current mitigation measures introduced as of mid-August, the number of COVID-19 infections will have doubled by the end of October, with active cases higher among the young, those of working age, and elderly individuals.

Among those of working age, the risk of infection would be higher for women than men, while among the elderly, the risk would be higher for men than women.

Across all age groups, mortality rates would be twice as high among men than among women.

The team says the findings highlight the importance of non-pharmaceutical mitigation measures (NPMM) to counteract the greater mortality risk that increased contact rates pose to the elderly.

They also say age- and sex-specific models improve infection and mortality forecasts
and that such models could be used to guide health policies and prioritize who should be tested and vaccinated first.

A pre-print version of the paper is available in the server medRxiv*, while the article undergoes peer review.

A new model based on three scenarios

Models designed to project disease spread have, therefore, consistently incorporated age as an important variable of transmission. However, another vital determinant is sex, which so far seems to have been overlooked in the previous modeling approaches, say the authors.

Now, Doerre and Doblhammer have developed a COVID-19 transmission model that incorporates age- and sex-specific contact rates to explore the effects that changes in mitigation measures may have on infection and death rates among men and women across different age groups.

The model was used to develop scenarios that assumed ongoing distancing measures versus easing contact restrictions across subdivisions of age group and gender. Three scenarios were developed with projections starting on 15th August, 2020, and ending on 31st October 2020.

The first scenario reflects a continuation of the distancing measures applied in mid-August and assumes that age-and sex-specific contacts are reduced by 80%.

The second scenario assumes a lifting of measures, mainly at working ages, and should reflect the return home from the workplace and the re-opening of establishments such as shops, cafés, and restaurants.

The third scenario extends the increase in contacts to children, adolescents, and young adults to reflect the re-opening of schools and venues mainly visited by young people.

What did the study find?

The model predicted that under the current control measures in place as of mid-August, the number of COVID-19 cases would increase by around two-fold by the end of October, rising from 10,572 on 15th August 2020 to 19,814 by October 31st.

The authors say there were three main lessons to be learned from the scenarios the model generated.

Firstly, just a small change in contact rates would have a significant impact on infection and mortality rates.

“This implies that the impact of contacts must be diminished considerably to allow increases in contacts without returning to an exponential growth of infections, hence underlining the high importance of the NPMM in the current phase of the pandemic,” writes the team.

Secondly, intergenerational contact would mean any relaxation of mitigation measures among young and working ages would lead to the highest infection rate among these age groups and lead to increased infection cases among the elderly.

The elderly would be at the highest risk of death, with older men always at a greater risk than women.

“Increases in contacts need to be accompanied by special measures protecting the elderly from death, without negative physical and mental health consequences due to quarantine and isolation measures,” say the authors.

Thirdly, small increases in contact rates would not alter the sex ratio infection and mortality rates. Among working ages, women would be at a greater risk of infection than men, while among the older men, the reverse would be true, and across all age groups, men would be twice as likely to die than women.

How can the model help?

The researchers say that although the forecasts made by this model only differ slightly from those of models that do not consider sex, age- and sex-specific models do provide better insights into the risk of infection and mortality among populations.

Using such models would help to ensure health policy measures target those who should be tested and vaccinated first.

The impact that biological sex and gender have on COVID-19 infection rates and outcomes needs to be considered in health policy and treatment decisions, concludes the team.


Journal reference:


Doerre A and Doblhammer G. Age- and Sex-Specific Modelling of the COVID-19 Epidemic. medRxiv, 2020. doi: https://doi.org/10.1101/2020.10.06.20207951
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Re: Coronavirus Reinfection / 2nd Wave Infection

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Scientists Confirm Nevada Man Was Infected Twice With Coronavirus

10/12/20


https://www.npr.org/sections/coronaviru ... oronavirus


A 25-year-old was infected twice with the coronavirus earlier this year, scientists in Nevada have confirmed. It is the first confirmed case of so-called reinfection with the virus in the U.S. and the fifth confirmed reinfection case worldwide.

The cases underscore the importance of social distancing and wearing masks even if you were previously infected with the virus, and they raise questions about how the human immune system reacts to the virus.

The two infections in the Nevada patient occurred about six weeks apart, according to a case study published Monday in the medical journal The Lancet. The patient originally tested positive for the virus in April and had symptoms including a cough and nausea. He recovered and tested negative for the virus in May.

But at the end of May, he went to an urgent care center with symptoms including fever, cough and dizziness. In early June, he tested positive again and ended up in the hospital.

"The second infection was symptomatically more severe than the first," the authors of the study write. The patient survived his second bout with COVID-19.

This is the second confirmed case of coronavirus reinfection in which the patient was sicker the second time. A patient in Ecuador also suffered a more serious case of COVID-19 the second time they were infected with the virus.

Scientists are unsure why this might be. In theory, the body's immune system should make antibodies after the first infection that help it combat the virus more effectively if the person is exposed to the same virus again.

"There are many reasons why a person might get sicker the second time around," explains Akiko Iwasaki, a professor of immunobiology at Yale University who was not involved in the Nevada study. For example, "they may have been exposed to a lot higher levels of the virus the second time around," she says, or the immune response from the first infection might be making the disease worse rather than better.

But, she stresses, "this is all very speculative" because scientists still have very little information about the mechanisms at play.

One of the biggest outstanding questions is how widespread reinfection might be. It's difficult to confirm cases in which a person is infected twice. Scientists must have the nasal swabs from both the first and second infection in order to compare the genomes of both virus samples.

Only the most advanced hospital and laboratory facilities have the equipment and personnel to do the genome sequencing and analyze the results. As a result, most cases of reinfection are likely going undetected.

Danny Altmann, a professor of immunology at Imperial College London, says it seems that about 90% of people who have experienced "a clear, symptomatic infection" have the antibodies to fight off another infection, "perhaps for about a year."

"Of course, that leaves 10% who don't" have sufficient antibodies to fight off a second infection, he wrote in an email to NPR. "[T]hey have precisely the same risk as anyone out there, thus a small but significant number of reinfections."

The authors of the new study also raise the possibility that cases of people being infected multiple times could have implications for the efficacy of a coronavirus vaccine, since some people exposed to the virus may not be mounting sufficient immune responses to protect themselves from a second infection.

But Iwasaki says such cases have no bearing on the efficacy of a future vaccine. The virus can deploy proteins to get in the way of the immune response, whereas a vaccine has none of those proteins, she explains. "The good thing about a vaccine is that it can induce much better immunity, a much longer lasting immunity, than the natural exposure to the the virus," she says.
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Re: Coronavirus Reinfection / 2nd Wave Infection

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Previous infection with other types of coronaviruses may lessen severity of COVID-19

Date:
October 6, 2020
Source:
Boston Medical Center
Summary:


https://www.sciencedaily.com/releases/2 ... 132110.htm


Being previously infected with a coronaviruses that cause the "common cold" may decrease the severity of severe acute respiratory syndrome coronavirus (SARS-CoV-2) infections, according to results of a new study. Led by researchers at Boston Medical Center and Boston University School of Medicine, the study also demonstrates that the immunity built up from previous non-SARS-CoV-2 coronavirus infections does not prevent individuals from getting COVID-19. Published in the Journal of Clinical Investigation, the findings provide important insight into the immune response against SARS-CoV-2, which could have significant implications on COVID-19 vaccine development.

The COVID-19 pandemic has led to more than 200,000 deaths in the US, and more than one million globally. There is a growing body of research looking into specific ways that the SARS-CoV-2 virus impacts different populations, including why some people are infected and are asymptomatic, as well as what increases ones mortality as a result of infection. There are a number of vaccines under development in order to determine what type of vaccine (mRNA, viral vector) will be most effective at preventing SARS-CoV-2 infections.

While SARS-CoV-2 is a relatively new pathogen, there are many other types of coronaviruses that are endemic in humans and can cause the "common cold" and pneumonia. These coronaviruses share some genetic sequences with SARS-CoV-2, and the immune responses from these coronaviruses can cross-react against SARS-CoV-2.

In this study, the researchers looked at electronic medical record data from individuals who had a respiratory panel test (CRP-PCR) result between May 18, 2015 and March 11, 2020. The CRP-PCR detects diverse respiratory pathogens including the endemic "common cold" coronaviruses. They also examined data from individuals who were tested for SARS-CoV-2 between March 12, 2020 and June 12, 2020. After adjusting for age, gender, body mass index, and diabetes mellitus diagnosis, COVID-19 hospitalized patients who had a previous positive CRP-PCR test result for a coronoavirus had significantly lower odds of being admitted to the intensive care unit (ICU), and lower trending odds of requiring mechanical ventilation during COVID. The probability of survival was also significantly higher in COVID-19 hospitalized patients with a previous positive test result for a "common cold" coronoavirus. However, a previous positive test result for a coronavirus did not prevent someone from getting infected with SARS-CoV-2.

"Our results show that people with evidence of a previous infection from a "common cold" coronavirus have less severe COVID-19 symptoms," said Manish Sagar, MD, an infectious diseases physician and researcher at Boston Medical Center, associate professor of medicine and microbiology at Boston University School of Medicine and the study's co-corresponding author. Another interesting finding, the authors note, is that immunity may prevent disease (COVID-19) in ways that are different from preventing infection by SARS-CoV-2. This is demonstrated by the fact that the patient groups had similar likelihoods of infection but differing likelihoods of ending up in the ICU or dying.

"People are routinely infected with coronaviruses that are different from SARS-CoV-2, and these study results could help identify patients at lower and greater risk of developing complications after being infected with SARS-CoV-2," said Joseph Mizgerd, ScD, professor of medicine, microbiology, and biochemistry at Boston University School of Medicine who is the study's co-corresponding author. "We hope that this study can be the springboard for identifying the types of immune responses for not necessarily preventing SARS-CoV-2 infection but rather limiting the damage from COVID-19."

This study was supported in part by grants from the National Institutes of Health (R35 HL-135756 to JPM, K24 AI-145661 to MS, 5T32 AI-052074-13 to PS, and R01 GM-122876 to LFW). Sagar's work is also facilitated by the Providence/Boston Center for AIDS Reearch (P30AI042853)

Story Source:

Materials provided by Boston Medical Center. Note: Content may be edited for style and length.

Journal Reference:

Manish Sagar, Katherine Reifler, Michael Rossi, Nancy S. Miller, Pranay Sinha, Laura White, Joseph P. Mizgerd. Recent endemic coronavirus infection is associated with less severe COVID-19. Journal of Clinical Investigation, 2020; DOI: 10.1172/JCI143380
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Re: Coronavirus Reinfection / 2nd Wave Infection

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Understanding COVID-19 immunity is crucial for developing vaccination strategies

10/14/20


https://www.news-medical.net/news/20201 ... egies.aspx

People who have recovered from COVID-19, and their close contacts, could hold the key to understanding how immunity to the disease develops, how long it lasts and what happens when immunity is lost.

The COVID PROFILE study, led by the Walter and Eliza Hall Institute, will use blood samples from people in Victoria to look in detail at immune responses to COVID-19, to reveal how people are protected - and how long people are protected - from future COVID-19 infection.

This information is vital for vaccine development - and could explain whether future vaccines can be given once, or whether they will need to be regularly repeated, like the annual influenza vaccine. This information will be critical for planning for the long-term 'COVID-normal' both locally and internationally.

At a glance

Melbourne researchers are investigating the immunity effects of COVID-19
The study is recruiting people who have had COVID-19 and their close contacts who haven't contracted the virus
The research will help inform decisions about vaccine development and other public health measures to control the virus, including operating in a 'COVID-normal' society

Understanding immunity against COVID-19


The study is looking for 300 adult volunteers, both those who have had COVID-19 and those who were close contacts (such as household members) but did not contract the disease. These participants will be followed for 12 months after their exposure to COVID-19, through regular blood samples and nose and throat swabs.

Lead researcher Professor Ivo Mueller said there were big questions in the scientific community about whether people could be re-infected with COVID-19 or how long immunity offered protection against the virus.

"While we know their immune response protects people after they recover from COVID-19, we suspect this protection wanes over time and reinfection of COVID-19 may be possible. We don't know how long this immunity lasts and whether it differs between people who have had severe, mild or asymptomatic infections," he said.

"Understanding immunity to COVID-19 is vital for developing vaccination strategies. It will also drive greater awareness and understanding to help us better manage this virus in the community.

"If we can predict the way immunity to the virus develops over time, whether and when people can be reinfected, and whether symptoms are less severe upon reinfection, we will be able to plan accordingly and stay ahead of the virus," he said.

Explaining different disease outcomes

As researchers across the world race to make sense of this global pandemic, many vital factors remain unknown.

" Concerningly, it may be possible that a second COVID-19 infection could be worse than the first, if immunity has waned. Our study will look closely at whether people could have more severe symptoms if they are re-infected."

- Ivo Mueller, Study Lead Researcher and Professor, Walter and Eliza Hall Institute

Study investigator Dr Vanessa Bryant said the research was crucial in helping to understand the wide range of symptoms experienced by people with COVID-19.

"Some people get severely ill and require hospitalization, while others are almost completely asymptomatic. Understanding why this happens will help us identify 'biomarkers' that could be used to predict which people may be at higher risk of contracting the virus or developing the most severe symptoms," she said.

"This will enable us to find new treatments that can help strengthen patients' immune systems to help them recover faster."


Source:

Walter and Eliza Hall Institute
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Re: Coronavirus Reinfection / 2nd Wave Infection

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SARS-CoV-2 may become endemic if reinfection proves commonplace, say researchers

10/14/20


https://www.news-medical.net/news/20201 ... chers.aspx

To date, a few verified repeat SARS-CoV-2 infections have been documented around the world.

" Should reinfection [with SARS-CoV-2] prove commonplace, and barring a highly effective vaccine delivered to most of the world's population, SARS-CoV-2 will likely become endemic."

- Jeffrey Shaman & Marta Galanti, Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University

For many viruses, a number of processes - particularly insufficient adaptive immune response, waning immunity, and immune escape - can allow subsequent reinfection. In the case of SARS-CoV-2, many questions remain about the nature of these immune responses and trajectories, though, say the authors, insight from other respiratory viruses points to the possibility of reinfection with SARS-CoV-2.

If this does happen, the pattern of endemicity that results will depend on the typical time scale at which individuals experience reinfection, seasonal differences in transmissibility, vaccine availability and efficacy, and social, immune, and innate factors that modulate virus transmissibility, say the authors.

In addition, the cyclic persistence of SARS-CoV-2 in human populations may be affected by ongoing opportunities for interaction with other respiratory pathogens, say the authors; it is possible infection with a different virus could provide some short-lived protection to SARS-CoV-2.

Greater monitoring of the clinical and population-scale interactions of SARS-CoV-2 with other respiratory viruses, particularly influenza viruses, is needed, they write. At the population scale, a possible overlap between influenza and SARS-CoV-2 outbreaks poses a serious threat to public health systems.

Conversely, the nonpharmaceutical interventions adopted to mitigate SARS-CoV-2 transmission (personal protective equipment, social distancing, increased hygiene, limited indoor gatherings) may reduce the magnitude of seasonal influenza outbreaks, note Shaman and Galanti.

Based on modeling of post-pandemic scenarios for SARS-CoV-2 to date, a duration of immunity similar to that of the other betacoronaviruses (~40 weeks) could lead to yearly outbreaks of SARS-CoV-2, the authors note, whereas a longer immunity profile, coupled with a small degree of protective cross-immunity from other betacoronaviruses, could lead to apparent elimination of the virus followed by resurgence after a few years.

"Other scenarios are, of course, possible, because there are many processes at play and much that remains unresolved," say the authors.

Source:

American Association for the Advancement of Science
Journal reference:

Shaman, J & Galanti, M (2020) Will SARS-CoV-2 become endemic?. Science. doi.org/10.1126/science.abe5960.
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Re: Coronavirus Reinfection / 2nd Wave Infection

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The Third Coronavirus Surge Has Arrived

This week’s COVID-19 cases and hospitalizations make clear that the U.S. is once again sinking deeper into the pandemic.

10/15/20


https://www.theatlantic.com/science/arc ... ge/616750/



After a month of warning signs, this week’s data make it clear: The third surge of the COVID-19 pandemic in the United States is underway. Outbreaks have been worsening in many states for more than a month, and new COVID-19 cases jumped 18 percent this week, bringing the seven-day average to more than 51,000 cases a day. Though testing rose by 8 percent nationally, that’s not enough of an increase to explain the steep rise in cases. Meanwhile, COVID-19 hospitalizations, which had previously been creeping upward slowly, jumped more than 14 percent from a week earlier.

Since last Wednesday, states reported 4,796 COVID-19 deaths, an increase of about 3 percent over the previous week. Since the start of the pandemic we have typically seen reported deaths lag behind reported cases by three to four weeks, although reporting delays seem to have worsened in some states, including Florida and Texas.

Our analysis is based on the official data we compile from 50 U.S. states, the District of Columbia, and five U.S. territories. Other sources confirm that the country is in trouble as we head further into fall: The New York Times, which collects official data at the county level, warned this morning that the U.S. is heading toward a new peak in COVID-19 cases. On the federal level, this week’s White House Coronavirus Task Force report (which is still not made public except by certain states) puts 26 states in the red zone based on new cases per capita, and an additional 19 states and the District of Columbia in the orange zone. As of this week, no U.S. states are in the task force’s green zone.

This week’s spike in new cases was spread across the country, rather than being concentrated in a few states, as we saw in the Northeast in the spring, in the Sun Belt in early June, and in the Midwest over the past few weeks. Seventeen states posted peak new-case days in the past week, including nine of 12 states in the Midwest and six of 11 states in the West.

Single-day case numbers have limited value because some states don’t report consistently or build up backlogs, then dump several days’ worth of test and case data in a single day. Nevertheless, when a state sets a new record for daily reported cases, it’s usually a bad sign. Of all the states that reported record highs this week, only Washington’s appears to be the result of reporting irregularities; the other 16 states all showed alarming overall case and hospital trends in the past week.


Cases in the Northeast, where the spread of COVID-19 slowed considerably during the summer after a dismal spring, are now rising: The seven-day average case count in the region has more than doubled in the past month. The Midwest has seen an 81 percent increase in COVID-19 cases in the same period.

The Dakotas continue to have the most cases per capita, with South Dakota recording 990 cases per 1 million people and North Dakota reporting 921 cases per 1 million, based on seven-day averages.

The other states reporting the largest number of cases per capita were Wisconsin, Montana, and Missouri. Note, though, that this might not reflect the reality on the ground in Missouri, as a database error led to what the state called an “incorrectly inflated” count of cases for October 10. Missouri officials have not yet explained whether any case numbers were actually wrong, or were simply allocated to the wrong date. We will correct our count once the state updates its figures.

Montana posted a week-over-week decline in cases, but the state’s hospitalization count continues to rise. Unfortunately, rising hospitalizations are the rule rather than the exception in states around the country this week.

Last week, 41 states saw increases in hospitalizations, and this week the numbers increased in 42 states. Every single state in the Midwest save North Dakota reported more hospitalizations this week than they did on October 8, and only the West had more than two states record drops in hospitalization figures in that period.

We’ve seen two previous hospitalization peaks in the national data, each with its own characteristics. From mid-March to mid-June, COVID-19 hospitalizations rose abruptly from zero to 60,000 and gradually declined to a low of just under 30,000 people hospitalized. Although outbreaks across the country contributed to the national numbers, these spring and early-summer hospitalizations were mostly concentrated in the Northeast. On June 21, national hospitalizations began increasing again as rising numbers in the South and West countered falling hospitalizations in the Northeast. As the case surge concentrated in the Sun Belt states came under control, hospitalizations gradually fell again to just under 30,000 people in mid-September, when the third surge began showing up in the hospital data.

The surge in hospitalizations we’re seeing now looks a little different: It’s less abrupt, and much more geographically widespread. And this time, more states that experienced major outbreaks earlier in the year are seeing hospitalizations rise again.

In New York and New Jersey, where stringent public-health measures brought the devastating spring surge under control and kept numbers down all summer, COVID-19 hospitalizations have gone up 53 and 34 percent, respectively, since October 1. In Texas, where hospitalizations soared in the summer and have steadily declined through the fall but never dropped below 3,000, a new upswing is underway: The number of people hospitalized in the Lone Star State has grown 32 percent in the past three weeks. More than 4,000 people in Texas are hospitalized with COVID-19.
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