Home CoronaVirus Collective immunity, vaccines will determine second wave of COVID

Collective immunity, vaccines will determine second wave of COVID

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UNITED STATES TODAY

Even before the first horrible phase of the COVID-19 pandemic has run its course, scientists are concerned about the second wave of the disease.

It could get worse than the first, killing tens of thousands of people who have done such a good job of shelter there that they remain virgin land. Or it could be a simple swell, with as many people being infected without symptoms as the immunity levels are higher than expected.

There is no crystal ball to look at, because there is so much crucial information left missing.

People who have been immunized with COVID-19? How long does immunity last? Will the virus reproduce like the flu and the common cold, peaking in the coldest months and falling during the warmest? Isn’t his deadly path discouraged regardless of the weather?

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Until there is a vaccine “, unfortunately it is not unlikely that we will see a second or even a third wave,” said Peter Marks, director of the Center for Biologics Evaluation and Research at US Food and Drug Administration, which oversees vaccines.

“I shiver when I think about it, but I think we have to be realistic. “

On March 19, 2020, Ludnie Emile, a healthcare professional, is preparing to test people for COVID-19 at their driving station for coronavirus testing. (Photo: Greg Lovett, The Palm Beach Post / USA TODAY Network)

Immunity: can you get coronavirus multiple times?

The first question that concerns every doctor is whether a person who has received COVID-19 is immune and, if so, for how long. People who have had mumps are immune to it for life. Versions of the common cold caused by different types of coronaviruses see immunity decline by a year. The variations are wide.

COVID-19 is such a new disease that there are no solid data on the immunity of survivors. But given its similarities to coronaviruses such as severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), it should transmit at least some immunity.

This is good news because so many people have acquired COVID-19 from SARS-CoV-2, the virus that causes the disease. Many more probably had it asymptotically and did not know it. Both groups probably have some immunity.

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It is impossible to know what percentage of the population is immune, as the United States does not yet have generalized tests, experts say. An answer is probably in months. Although immunity is not permanent, the virus may have infected enough people to make it difficult to find new victims.

“It would mean that we would achieve collective immunity through natural immunity” before a vaccine is even developed, said Marc Lipsitch, professor of epidemiology at Chan School of Public Health at Harvard, who is co -author of an article in the journal Science modeling what COVID-19 might look like after the initial pandemic has passed.

When he returns, he risks hitting the hardest areas not severely infected the first time, said Gregory Poland, professor of medicine at the Mayo Clinic in Rochester, Minnesota, and editor of the journal Vaccine.

“This epidemic mainly occurred on both coasts. The second wave will take place inside the county, where there are a lot of sensitive people, “he said.

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Will the coronavirus disappear in summer?

Another factor is whether the virus survives longer in cooler, drier weather. This is why the flu is more common in winter, its virus survives longer and people are more likely to be indoors in close contact.

“We really don’t know if it’s going to bounce back when people start to go outside or if the warmer weather is really going to help us,” said Michael Mina, professor of epidemiology at the Center for Communicable Disease Dynamics at Chan School of Public Health at Harvard.

“If it doesn’t happen in the summer, we would all be very surprised if we don’t see a reemergence in the fall,” he said.

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In this case, the COVID-19 sweet spot could be the same as the flu, approximately from October to May, with a peak between October and November, suggests modeling. If it behaves like the flu, it will travel to the southern hemisphere for the winter there, and then return to the northern hemisphere for its cold months.

“To anthropomorphize, the virus will return here in search of new victims,” ​​said Poland.

The first wave of the disease, which the world is currently experiencing, struck so hard because no one had immunity. It could eventually fall into an annual recurrence pattern, like the flu.

If they were made worse by the annual wave of winter flu, hospitals across the country would be taxed more.

A fall spike also seems likely when children return to school, said Mike Reid, professor of infectious diseases at the University of California at San Francisco.

To avoid this, large-scale tests should be available and contact tracing should be in place to find all those exposed and have them isolate themselves for at least 14 days.

“Given the potential for repeated waves, the more it will be possible to set up a quick jump on each new peak and each fence each person infected with enveloping health services is going to be crucial,” said Reid.

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What we do is important

Experts say our behavior will play an important role in the size and severity of subsequent waves. People can help by staying alert to hand washing, continuing to distance themselves, and wearing masks in public.

Add to that more monitoring and widely available testing, the chances of improving the second wave are smaller than the first.

As states begin to relax restrictions, the United States will indeed become a massive series of experiments. Epidemiologists will watch closely, said Lipsitch.

Some areas will reopen schools, while others will have staggered school days, so not all students are there at the same time. The same will happen in the workplace, even if more work is done at home. Some areas “cocoon” the elderly, paying particular attention to ensuring that they are not exposed. Others may create “passports” for immunized people, if there is data showing that the infection confers immunity.

“There are a lot of things we can do, and we don’t yet know how they will work,” said Lipsitch.

Temperature testing in schools and businesses, as is now the case in Asia, could be helpful.

“It is not the most sensitive test in the world, but it is a screen that keeps people aware that they have an obligation not to infect other people,” said Barry Bloom, professor of health. public at the Chan School of Public Health at Harvard.

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The price of health is eternal vigilance

Vigilance will be key, experts say.

“No one can tell when the coast is clear,” said William Hanage, professor of epidemiology at Chan School of Public Health at Harvard.

COVID-19 is fairly easy to spread and with a sufficiently long incubation period, it is possible to go from 100 known cases a week to 65,000 a few weeks later. “One slip and we could see it resume,” he said.

There is a cautionary tale of the 2003 SARS epidemic in Toronto, which infected 375 people and killed 44. The city took the precautions were expanded from March, but were lifted in May when it looked like the epidemic was over. This was not the case.

“Toronto has taken the brakes,” said Hanage. “They had a flare and it took them weeks to get it under control. “

Contact journalist Elizabeth Weise at [email protected]

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On Friday, the former head of the global rapid response team at the Centers for Disease Control and Prevention explained what we know about the COVID-19 pandemic. (April 10)

AP Domestic

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