Coronavirus Reinfection / 2nd Wave Infection

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Coronavirus Reinfection / 2nd Wave Infection

Post by trader32176 »

Researchers say Hong Kong man is first confirmed to have Covid-19 twice — but more research is needed

8/24/20 ... index.html

A 33-year-old man living in Hong Kong had Covid-19 twice this year, according to preliminary research out of China.

The pre-print study — which the University of Hong Kong said on Monday has been accepted to publish in the journal Clinical Infectious Diseases — found that the man’s second case of Covid-19 occurred 142 days after the first.

The study also noted that in the first case, the man showed symptoms but in the second case he was asymptomatic, in that he did not show any noticeable symptoms.

During his first episode of illness, the patient had a cough, sore throat, fever and headache for three days, according to the study. He tested positive for Covid-19, the disease caused by the novel coronavirus SARS-CoV-2, on March 26.

Then during his second episode, the patient was returning to Hong Kong from traveling in Spain via the United Kingdom, and he tested positive during his entry screening at the Hong Kong airport on August 15, according to the study. The man was then hospitalized again but remained asymptomatic.

For the study, researchers at the University of Hong Kong and various hospitals in Hong Kong analyzed specimens collected from the patient 10 days after his symptoms emerged in the first episode and then one day after hospitalization for the second episode. They analyzed genetic material in those specimens.

The genetic analysis showed that the first infection was from a strain of the coronavirus most closely related to strains from the United States or England, which were collected in the spring, and the second was most closely related to strains from Switzerland and England, which were collected in July and August.

“This case illustrates that re-infection can occur even just after a few months of recovery from the first infection. Our findings suggest that SARS-CoV-2 may persist in humans as is the case for other common-cold associated human coronaviruses, even if patients have acquired immunity via natural infection or via vaccination,” the researchers wrote in their study.

“In summary, reinfection is possible 4.5 months after a first episode of symptomatic infection. Vaccination should also be considered for persons with known history of COVID-19,” they wrote. “Patients with previous COVID-19 infection should also comply with epidemiological control measures such as universal masking and social distancing.”

Some context: The researchers called this the “first case” of re-infection of Covid-19 in their paper, but other experts are calling for more research before naming this case truly the world’s first.

“What I think is really important is that we put this into context,” said Maria Van Kerkhove, the World Health Organization's technical lead for coronavirus response and head of the emerging diseases and zoonoses unit, during a media briefing in Geneva on Monday.

“There’s been more than 24 million cases reported to date. And we need to look at something like this on a population level. And so it's very important that we document this and that, in countries that can do this if sequencing can be done that would be very, very helpful. But we need to not jump to any conclusions,” Van Kerkhove said. “Even if this is the first documented case of reinfection, it is possible of course because with our experience with other human coronaviruses, and the MERS coronavirus and the SARS-CoV-1 coronavirus, we know that people have an antibody response for some time but it may wane.”
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Re: Hong Kong man is first confirmed to have Covid-19 twice

Post by TimGDixon »

I saw this yesterday - i think this is only the tip of the iceberg... this isn't going away and plasma containing antibodies are not the be-all, end-all. Its good for emergency use but there is also evidence it may suppress the immune system. Keep up the good research Trader - we should put you on our team :-)
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Re: Hong Kong man is first confirmed to have Covid-19 twice

Post by trader32176 »

Expect COVID-19 reinfections, warns top doctor, as more cases confirmed

8/26/20 ... dad114022a

Two cases of COVID-19 infection in patients that had previously had the virus have been reported in Europe.
It follows the first confirmed case of coronavirus reinfection in a man in Hong Kong, who tested positive twice for the disease.
Researchers from the University of Hong Kong said the man was reinfected four-and-a-half months after he first caught the virus, which suggested the pandemic can infect multiple times.

The man had mild symptoms the first time and none the second time; his more recent infection was detected through screening and testing at the Hong Kong airport.

The latest cases - confirmed in Belgium and the Netherlands - will fuel concern about the effectiveness of patient's immunity.
Belgian virologist Marc Van Ranst said the country's case was a woman who had contracted COVID-19 for the first time in March and then again in June, Reuters reports.

The National Institute for Public Health in the Netherlands said it had also observed a case of re-infection in an older person, Dutch media reports.
Australia's Deputy Chief Medical Officer Michael Kidd told Today cases of reinfection should be expected as the pandemic develops.
He confirmed there were "different strains" of the virus.
"It's not surprising that we're seeing someone who has been infected a second time.
"We do know from other coronaviruses, particularly those that cause symptoms of the common cold, that people develop immunity which can then reduce quite rapidly over time."

More research needs to be completed on reports people are becoming reinfected, Monash University Associate Professor Julian Elliott said.
"We really need to understand how common that is actually and particularly what is the clinical course of someone who's reinfected … there's a lot more to learn."
He confirmed there were "different strains" of the virus.
Whether people who have had COVID-19 are immune to new infections and for how long are key questions that have implications for vaccine development and decisions about returning to work, school and social activities.
Even if someone can be infected a second time, it's not known if they have some protection against serious illness, because the immune system generally remembers how to make antibodies against a virus it's seen before.
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Re: Hong Kong man is first confirmed to have Covid-19 twice

Post by trader32176 »

Doctors find possible case of Covid-19 reinfection in US

8/29/20 ... index.html

A 25-year-old Nevada man appears to be the first documented case of Covid-19 reinfection in the United States.

Genetic tests indicate the patient was infected with two different varieties of the virus, a team at the University of Nevada Reno School of Medicine and the Nevada State Public Health Laboratory reported.

The patient was first diagnosed with coronavirus in April after he had a sore throat, cough, headache, nausea and diarrhea, the researchers wrote in a pre-print study posted Thursday. He got better around April 27, and he tested negative for the virus twice afterwards.

He continued to feel well for about a month. Then, on May 31, he sought care for fever, headache, dizziness, cough, nausea and diarrhea. Five days later, he was hospitalized and required ongoing oxygen support. He was tested again for Covid-19 and the results were positive.

The Nevada researchers examined genetic material from both coronavirus specimens collected from the man. Their analysis suggests he had two distinct viral infections.
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Re: Coronavirus Reinfection - Hong Kong man is first confirmed to have Covid-19 twice

Post by trader32176 »

Strength, duration of immunity will shape the future trajectory of COVID-19

9/21/20 ... ID-19.aspx

New research suggests that the impact of natural and vaccine-induced immunity will be key factors in shaping the future trajectory of the global coronavirus pandemic, known as COVID-19. In particular, a vaccine capable of eliciting a strong immune response could substantially reduce the future burden of infection, according to a study by Princeton researchers published in the journal Science Sept. 21.

" Much of the discussion so far related to the future trajectory of Covid-19 has rightly been focused on the effects of seasonality and non-pharmaceutical interventions [NPIs], such as mask-wearing and physical distancing. In the short term, and during the pandemic phase, NPIs are the key determinant of case burdens. However, the role of immunity will become increasingly important as we look into the future."

-Chadi Saad-Roy, co-first author, Ph.D. candidate in Princeton's Lewis-Sigler Institute for Integrative Genomics

"Ultimately, we don't know what the strength or duration of natural immunity to SARS-CoV-2 -- or a potential vaccine -- will look like," explained co-first author Caroline Wagner, an assistant professor of bioengineering at McGill University who worked on the study as a postdoctoral research associate in the Princeton Environmental Institute (PEI).

"For instance, if reinfection is possible, what does a person's immune response to their previous infection do?" Wagner asked. "Is that immune response capable of stopping you from transmitting the infection to others? These will all impact the dynamics of future outbreaks."

The current study builds on Princeton research published in Science May 18 that reported that local variations in climate are not likely to dominate the first wave of the COVID-19 pandemic and included many of the same authors, who are all affiliated with PEI's Climate Change and Infectious Disease initiative.

In the most recent paper, the researchers used a simple model to project the future incidence of COVID-19 cases -- and the degree of immunity in the human population -- under a range of assumptions related to how likely individuals are to transmit the virus in different contexts. For example, the model allows for different durations of immunity after infection, as well as different extents of protection from reinfection. The researchers posted online an interactive version of model's predictions under these different sets of assumptions.

As expected, the model found that the initial pandemic peak is largely independent of immunity because most people are susceptible. However, a substantial range of epidemic patterns are possible as SARS-CoV-2 infection -- and thus immunity -- increases in the population.

"If immune responses are only weak, or transiently protective against reinfection, for example, then larger and more frequent outbreaks can be expected in the medium term
," said co-author Andrea Graham, professor of ecology and evolutionary biology at Princeton.

The nature of the immune responses also can affect clinical outcomes and the burden of severe cases requiring hospitalization, the researchers found. The key question is the severity of subsequent infections in comparison to primary ones.

Importantly, the study found that in all scenarios a vaccine capable of eliciting a strong immune response could substantially reduce future caseloads. Even a vaccine that only offers partial protection against secondary transmission could generate major benefits if widely deployed, the researchers reported.

Factors such as age and superspreading events are known to influence the spread of SARS-CoV-2 by causing individuals within a population to experience different immune responses or transmit the virus at different rates. "Our models show that these factors do not affect our qualitative projections about future epidemic dynamics," said Bryan Grenfell, the Kathryn Briger and Sarah Fenton Professor of Ecology and Evolutionary Biology and Public Affairs and an associated faculty member in PEI. Grenfell is a co-senior author on the paper with C. Jessica Metcalf, associate professor of ecology and evolutionary biology and public affairs and also a PEI associated faculty member.

"As vaccine candidates emerge, and more detailed predictions of future caseloads with vaccination are needed, these additional details will need to be incorporated into more complex models," Grenfell said.

The study authors also explored the effect of "vaccine hesitancy" on future infection dynamics. Their model found that people who decline to partake in pharmaceutical and non-pharmaceutical measures to contain the coronavirus could nonetheless slow containment of the virus even if a vaccine is available.

"Our model indicates that if vaccine refusal is high and correlated with increased transmission and riskier behavior such as refusing to wear a mask, then the necessary vaccination rate needed to reach herd immunity could be much higher," said co-author Simon Levin, the James S. McDonnell Distinguished University Professor in Ecology and Evolutionary Biology and an associated faculty member in PEI. "In this case, the nature of the immune response after infection or vaccination would be very important factors in determining how effective a vaccine would be."

"When so much uncertainty in the underlying processes exists, it can be challenging to make accurate projections about the future," Grenfell said. "We argue in this study that ultimately, a family of both simple and more complex models is the best way to proceed under these circumstances. Comparing the predictions of these models carefully and then coming up with a carefully averaged picture of the future -- as with weather prediction -- can be very helpful."

One of the main takeaways of the study is that monitoring population-level immunity to SARS-CoV-2, in addition to active infections, will be critical for accurately predicting future incidence.

"This is not an easy thing to do accurately, particularly when the nature of this immune response is not well understood," said co-author Michael Mina, an assistant professor at the Harvard School of Public Health and Harvard Medical School. "Even if we can measure a clinical quantity like an antibody titer against this virus, we don't necessarily know what that means in terms of protection."

"Studying the effects of T-cell immunity and cross-protection from other coronaviruses are important avenues for future work," Metcalf said.
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Re: Coronavirus Reinfection - Hong Kong man is first confirmed to have Covid-19 twice

Post by trader32176 »

Exploring how COVID-19 pandemic trajectory might unfold in the future

9/22/20 ... uture.aspx

Researchers who adapted standard epidemiological models to explore how the COVID-19 pandemic trajectory might unfold in the next five years report diverse scenarios ranging from recurring severe epidemics to elimination. Their work emphasizes how dependent the future course of the pandemic is on the nature of the adaptive immune response to this virus and on the efficacy of future potential vaccines. The duration and severity of future COVID-19 cases will depend on the strength of both natural and vaccine-derived immunity against the SARS-CoV-2 pathogen.

However, there is still uncertainty about both. Here, to explore how variations in immune responses could impact the magnitude and timing of COVID-19 cases in the next five years, Chadi Saad-Roy and colleagues adapted a series of standard epidemiologic models of the spread of infection (the SIR and SIRS models, respectively). They used these adapted models to evaluate results of four future scenarios that consider different outcomes for the nature of the adaptive immune response to SARS-CoV-2 infection, the effect of transmission rate seasonality, the adoption of non-pharmaceutical interventions, and the availability and effectiveness of a vaccine.

Depending on these variations, dramatically different immunity landscapes and burdens of critically severe cases could emerge, they say, ranging from sustained epidemics to near elimination. The results underscore that understanding the immunology of secondary infection - which impacts the number of those susceptible to the virus - is critical. They also reveal how the pandemic trajectory will be substantially altered by mass deployment of vaccines, though, this is strongly dependent on vaccine efficacy.

Their work also shows that relying on the status of infection of an individual as the main "observable" during an ongoing epidemic is not sufficient to characterize the complex immune landscape generated by the pandemic.

Regular testing of antibody presence and correlates of protection such as T cell immunity are critical, to accurately characterize population-level natural and vaccinal immunity to this pathogen. The authors note that in order to focus on immune dynamics, they made several simplifying assumptions.
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Re: Coronavirus Reinfection

Post by trader32176 »

Molecular analysis of COVID-19's second wave shows mutant viruses linked to rapid spread

9/24/20 ... pread.aspx

Molecular analysis of COVID-19's powerful second wave in Houston – from May 12 to July 7 – shows a mutated virus strain linked to higher transmission and infection rates than the coronavirus strains that caused Houston's first wave.

Gene sequencing results from 5,085 COVID-positive patients tested at Houston Methodist since early March show a virus capable of adapting, surviving and thriving – making it more important than ever for physician scientists to understand its evolution as they work to discover effective vaccines and therapies.

In the second major gene sequencing study conducted by James M. Musser, M.D., Ph.D., chair of the Department of Pathology and Genomic Medicine at Houston Methodist, and his team of infectious disease pathologists, they found that the two waves affected different types of patients.

The study, preprinted under the title "Molecular architecture of early dissemination and massive second wave of the SARS-CoV-2 virus in a major metropolitan area," provides the first molecular characterization of SARS-CoV-2 strains causing two distinct COVID-19 disease waves, a problem now occurring extensively in many European countries.

Houston's second wave hit significantly younger patients who had fewer underlying conditions and were more likely to be Hispanic/Latino living in lower income neighborhoods.

In addition, virtually all COVID-19 strains studied during the second wave displayed a Gly614 amino acid replacement in spike protein – the part of the virus that mediates invasion into human cells, gives the coronavirus its telltale crown-like appearance and is the major focus of vaccine efforts worldwide.

While this mutation has been linked with increased transmission and infectivity, as well as a higher virus load in the nasopharynx, which connects the nasal cavity with the throat, the mutation did not increase disease severity, researchers said.

The findings reinforce researchers' concerns of the virus gaining momentum through naturally occurring mutations capable of producing mutant viruses that can escape vaccines – dubbed 'escapians' – or mutants that can resist drugs and other therapies.

" This extensive virus genome data gathered from Houston's earliest cases to date, coupled with the growing database we are building at Houston Methodist, will help us identify the origins of new infection spikes and waves. This information can be an especially helpful community resource as schools and colleges re-open and public health constraints are further relaxed."

-James M. Musser, M. D, Ph.D, Study Corresponding Author, Chair, Department of Pathology and Genomic Medicine, Houston Methodist

Given the urgency of finding effective treatments for COVID-19, the preliminary report is posted to the preprint server medRxiv, and a manuscript is under peer-review at a prominent scientific journal. This preprint is not the final version of the article.

Wesley Long, M.D., Ph.D., a first author of the study, said it's critical for people throughout the region, state and nation continue to keep preventive practices in place. "To avoid that third wave and keep cases low, we have to keep wearing masks and social distancing and testing and staying home if we're sick," Long said. "The virus is still out there and still circulating."

The more scientists can understand about this pandemic and put it in context with what they understand about other coronaviruses, Long adds, the more able they may be to discover treatments or vaccines that might protect us from not just COVID-19, but also future pandemics.
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Re: Coronavirus Reinfection

Post by trader32176 »

Prevalence of SARS-CoV-2 with D614G mutation in a second wave infection in Houston

9/24/20 ... uston.aspx

A recent study reveals that the genetic variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detected in the initial phase of coronavirus disease 2019 (COVID-19) pandemic differ from the variants detected in a massive second wave of infection in Houston, Texas. The study is currently available on the medRxiv* preprint server.

According to the World Health Organization (WHO), the rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in over 32 million confirmed COVID-19 cases, including 979,000 deaths worldwide, as of 25 September 2020. In the United States, the regions worst hit by the COVID-19 pandemic include Seattle and New York City.

In the Houston metropolitan area, which is the 4th largest and ethnically diverse city in the United States, the first confirmed case of COVID-19 was registered on 5 March 2020, and the community transmission of SARS-CoV-2 started a week later.

In Houston, a continuous effort has been made to identify positive COVID-19 cases and evaluate genomic variants of SARS-CoV-2 since the initial phase of the pandemic. The effort has been significantly expanded with the emergence of a second wave of SARS-CoV-2 infection in late May 2020.

Current study objective

The current study by researchers from the Houston Methodist Hospital, University of Chicago, and the University of Texas at Austin was designed to evaluate the viral introduction events in the Houston metropolitan area and identify the genomic variants of SARS-CoV-2 that have infected people during the initial wave and a second prominent wave of SARS-CoV-2 infection.
Study design

The COVID-19 trajectory graph demonstrated that the number of SARS-CoV-2 infected people peaked around mid-April, followed by a reduction in case numbers until 11 May. However, there was a sharp increase in case numbers beginning on 12 June. Considering this trajectory, the scientists defined the 1st wave of infection as 5 March – 11 May 2020, and the 2nd wave as 12 May – 7 July.

In the early phase of the 1st wave, they tested 3,080 patient samples and found 406 SARS-CoV-2 positive cases. These cases represent 40% of all confirmed cases in the Houston metropolitan area. During the entire study period, they identified 9,121 SARS-CoV-2 positive cases out of 55,800 suspected cases. These cases represent 17% of all confirmed cases in the metropolitan area. According to the scientists, the viral strains they identified represent all COVID-19 cases during the 1st and 2nd waves of infection.
Important observations

By analyzing the characteristics of patients, the scientist observed that the people affected in the second wave were much younger, had lower numbers of comorbidities, lived in low-income families, and was mostly Hispanic/Latino.

Regarding genetic variants of SARS-CoV-2, the scientists identified a diverse-range of viral genomes in the 1st wave, and the majority of these strains belonged to the clades G, GH, GR, and S. These are the major genetic clades causing COVID-19 globally.

About 82% and 99.9% of the viral strains in the 1st and 2nd waves had D614G mutation in the spike protein, respectively. The D614G mutation has been shown to increase the transmission efficiency and infectivity of SARS-CoV-2.

The presence of different variants of SARS-CoV-2 in the early phase of 1st wave indicates several independent viral entry events in Houston instead of the introduction and transmission of a single variant.

Using machine learning models, they observed that the acquisition of D614G mutation was not correlated with the disease outcomes. However, people infected with the mutated variant of SARS-CoV-2 showed significantly higher viral load in the nasopharynx.

Analysis of the genetic sequence coding for the spike protein identified 470 single nucleotide polymorphisms, of which 285 caused amino acid changes. These amino acid substitutions were identified in each spike protein domain and subunit. The most frequently occurring substitution was D614G.

Furthermore, the scientists generated a spike protein construct carrying D614G mutation and observed that the mutated spike protein has higher thermostability and increased expression level. Pseudotyped viruses with the D614G variant of the spike protein showed significantly higher infectivity for host cells in vitro.

Additionally, they created 13 receptor-binding domain (RBD) variants carrying D614G mutation along with an additional single amino acid substitution that had been identified in the genome analysis data.

They observed that the majority of these variants have a high affinity for the angiotensin-converting enzyme (ACE) receptor.

Interestingly, they observed that of these variants, three (F338L, S373P, and R408T) had significantly reduced affinity for a monoclonal neutralizing antibody, namely CR3022, which is known to disrupt the spike protein homotrimerization interface.

Of these variants, S373P is located one amino acid away from the CR3022-specific epitope. These observations indicate that SARS-CoV-2 acquiring mutations in the RBD can potentially escape the antibody-mediated host immune responses.
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Re: Coronavirus Reinfection

Post by trader32176 »

SURVIVING THE 2ND WAVE: Inflammation and permanent lung damage from COVID-19

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Re: Coronavirus Reinfection / 2nd Wave Infection

Post by trader32176 »

First and Second Waves of Coronavirus

Updated Aug. 14, 2020 ... oronavirus

In many parts of the world, cases of COVID-19 are declining, while other areas are seeing spikes. But the pandemic is still evolving. Doctors, public health experts and researchers are trying to answer tough questions: When will this first wave be over, and will there be a second wave of COVID-19 in the fall?

Because so little is known about the SARS-CoV-2, the coronavirus that causes COVID-19, these are not easy questions to answer, but Lisa Maragakis, M.D., M.P.H., a specialist in infectious disease at Johns Hopkins Medicine, sheds light on what we know now.

Is the first wave of coronavirus over?

No, we’re still in the first wave. In some sense, the spread of the coronavirus so far has been more like a patchwork quilt than a wave. The COVID-19 pandemic in the U.S. is affecting different areas throughout the country in different ways at different times.

Some cities and towns experienced severe outbreaks and appear to be recovering, other places have not had many cases, and some states are only now experiencing a rise in COVID-19. It’s also clear that places where people live or work closely together (nursing homes, multigenerational households, prisons and businesses such as meat packing plants) have tended to see more spread of the coronavirus.

Although some areas are reporting declining numbers of infections and deaths, localized outbreaks at nursing homes and “superspreader” events — in which one infected person transmits the virus to many others at a gathering — continue to occur.

COVID-19: Why are surges occurring across the U.S.?

Why are there coronavirus spikes?

As communities begin to reopen, people are understandably eager to be able to go out and resume some of their regular activities. But we don’t yet have an effective therapy or vaccine, so the reopenings are intended to take place safely while maintaining social distancing, and masking and hand-washing as we’ve done over the last few months. Some people relax these infection prevention efforts as soon as places begin to reopen, and this can cause the number of coronavirus infections to rise.

There seems to be a long delay between a policy change in a community and when its effects show up in the COVID-19 data. As locations reopen businesses, they might not see any effects, such as an increase in the number of COVID-19 cases or hospitalizations, a week or even two weeks later. It seems to take much longer, perhaps as many as eight weeks, for effects to appear in the population-level data.

When a person is exposed to the coronavirus, it can take up to two weeks before they become sick enough to go to the doctor, get tested and have their case counted in the data. It takes even more time for additional people to become ill after being exposed to that person, and so on. Several cycles of infection are likely to occur before a noticeable increase shows in the data that public health officials use to track the pandemic.

So when an area relaxes social distancing guidelines and “reopens,” the effects of that change might take a month or more to be seen. Of course, surges after reopening also depend on the behaviors of people when they start moving around more. If everyone continues to wear masks, wash their hands and practice social distancing, reopening will have a much lower impact on transmission of the virus than in communities where people do not continue these safety precautions on a widespread basis.

Is warm weather helping to lessen COVID-19's impact?

In the beginning of the pandemic, some experts wondered if warmer weather would slow down the spread of the coronavirus. Some respiratory illnesses, like colds and influenza (flu), are more common in the colder months, so researchers are trying to find out if this is true of COVID-19.

In one study, warm weather reduced coronavirus spread by 20%. Even if that trend is accurate across the country, the pandemic might slow down but it would be unlikely to end. So far, we have not seen evidence that SARS-CoV-2 transmission is slowed by warm weather.

Why are experts concerned about a second wave of coronavirus?

A second surge could happen before fall, with human behavior playing a major part. People are frustrated. Cellphone data are showing decreased social distancing. It takes weeks for the number of COVID-19 cases to change after a major behavior shift, so in June, we're seeing a reflection now of what was going on in early April. Since then, we’ve had better weather, Passover, Easter, Mother’s Day and Memorial Day. By the end of this summer, we're going to see the results of behavior changes that took place over those events and that period of time.

When predicting the future of the COVID-19 pandemic, experts look to other pandemics and the behavior of other viruses. Examples include the 1918 flu pandemic and the 2009 H1N1 flu epidemic. Both of these events began with a mild wave of infections in the spring, followed by another surge of cases in the fall.

Around the world, according to the World Health Organization, a resurgence of COVID-19 is a threat. Areas that were hit hard by the coronavirus in the winter, such as China, Italy and Iran, are still on guard for outbreaks. Some countries have already relaxed closures and distancing measures, even though new infections are still occurring. Even countries with strict lock-down policies over the winter, such as China, are seeing new cases.

Will a second wave of coronavirus be worse in the fall?

It could be, because people infected with the coronavirus are capable of transmitting it to others even before they develop any symptoms themselves, and we are worried about what will happen when the virus circulates along with other respiratory viruses like influenza.

When the coronavirus first appeared in the U.S. in early 2020, it started with a very small number of infected people, so it took longer to spread. A second wave could start with many unknowing coronavirus carriers in many different areas, and the risk of transmission increases when people spend more time together indoors, which is more common in the fall and winter months.

It's a challenge because now there are so many different chains of infection to follow. At the beginning, we had the opportunity to do contact tracing and quarantine, but now that the disease is widespread, it makes it harder to detect and control transmission.

Can I get coronavirus twice?

Researchers are eager to answer this question. Right now, it’s not known. If SARS-CoV-2 behaves like other coronaviruses, such as those that cause mild colds, some experts say you might be immune for a while and then lose that immunity within a few months. Studies are ongoing, but we don’t yet know whether an antibody response to SARS-CoV-2 protects someone from getting the infection again at a later time.

COVID-19 in the Fall: Other diseases could complicate the picture

An increase in COVID-19 cases in the fall could be troublesome, because seasonal flu is likely to be accelerating at the same time. If the coronavirus surges in the fall and the flu season is bad, the combination could put hospitals and patients at risk. In the U.S. during the 2019–2020 flu season, the Centers for Disease Control and Prevention reported 39 million cases and 24,000 deaths.

Another concern is that since the COVID-19 pandemic began, far fewer children have been getting their regular vaccinations. An outbreak of pertussis (whooping cough), measles, flu or other preventable disease in children could also complicate the picture, making it harder for doctors and hospitals to care for all patients.

When will we have herd immunity from coronavirus?

Herd immunity is a public health term. When enough people in a community have immunity from a disease, it protects the community from outbreaks of that disease.

Infectious disease experts at The Johns Hopkins University explain that about 70% of the population needs to be immune to this coronavirus before herd immunity can work. People might be immune from the coronavirus if they have already had it, but we don’t know this yet. A widely available, safe and effective vaccine may not be available for many months.

Preparing for a Second Wave of Coronavirus

Doctors, clinics and hospitals recognize the chance that COVID-19 cases could start increasing in the fall. They are working with manufacturers to stock up on equipment, and they are continuing their policies for protecting patients and staff members.

Here's what you can do now

Continue to practice COVID-19 precautions, such as physical distancing, hand-washing and mask-wearing.
Stay in touch with local health authorities, who can provide information if COVID-19 cases begin to increase in your city or town.
Make sure your household maintains two weeks’ worth of food, prescription medicines and supplies.
Work with your doctor to ensure that everyone in your household, especially children, is up to date on vaccines, including this year’s flu shot when it is available.
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