When will a second wave of the coronavirus hit, and what will it look like? – USA TODAY

Got a minute? Here's how you can help slow the spread of Coronavirus COVID-19 in under 60 seconds. USA TODAY

Even before the first horrific phase of the COVID-19 pandemic has run its course, scientists are worried aboutthe second wave of the disease.

It could crashworse than the first, killing tens of thousands of people who did such a good job of sheltering in place they remain virgin ground for the virus. Or it could be a mere swell, with so many people having been infected without symptoms that levels of immunity are higher than realized.

There is no crystal ball to look to, because so many crucial pieces of information remainmissing.

Are people who've had COVID-19immune? How long does immunity last? Will the virus play out likeinfluenza and the common cold, peaking during cooler months and fallingduring warmer ones? Is itsdeadly path undeterred whatever the weather?

Coronavirus Watch: Sign up for daily updates to your inbox

Until theres a vaccine its unfortunately not unlikely that we may see a second wave or even a third wave, said Peter Marks, director of the U.S. Food and Drug Administrations Center for Biologics Evaluation and Research, which oversees vaccines.

I shudder to think of that, but I think we have to be realistic."

Health care worker Ludnie Emile prepares to test patients for COVID-19 at a drive-thru coronavirus testing station in Palm Springs, Fla. on March 19.(Photo: Greg Lovett, The Palm Beach Post/ USA TODAY Network)

The first question on every doctors mind is whether someone who hashad COVID-19 is immune, and if sofor how long. People who've had mumpsare immune from it for life. Versions of the common coldcaused by different types of coronavirus seeimmunity wanewithin a year. Variations are wide.

COVID-19 is such a new disease that there is no solid dataon the immunity of survivors. But given its similarities to coronaviruses such as severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), it's expected to conveyat least some immunity.

Thats good news because so many people have contracted COVID-19 from SARS-CoV-2, the virus that causes the disease. Many moreprobably have had it asymptomatically and didnt know. Both groups likely have some immunity.

A class war? A global power shift?How experts see the future after coronavirus.

What percentage of the population is immuneis impossible to know because the United States doesnt yet have widespread testing, experts say. An answer is likely months away. Even if immunity isn'tlifelong, the virus may have infected enough people to make it hardfor it to find new victims.

It would mean wed be getting to herd immunity through natural immunity even before a vaccine is developed, said Marc Lipsitch, a professor of epidemiology at Harvards Chan School of Public Health, whoco-wrote a paper in the journal Science modelingwhat COVID-19 might look like after the initial pandemic has passed.

When itcomes back, its likely to hit hardest areas not severely infected the first time, said Gregory Poland, a professor of medicine at the Mayo Clinic in Rochester, Minnesota, and editor-in-chief of the journal Vaccine.

This outbreak has predominantly been on the two coasts. Wave 2 will be in the interior of the county where there are a lot of susceptible people, he said.

America has suffered great loss before.Here's how we may learn to cope with coronavirus death toll.

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

We have no idea really whether this is going to bounce back the moment people start going back outdoors or if the warmer weather is actually going to help us out, said Michael Mina, a professor of epidemiology at the Center for Communicable Disease Dynamics at Harvard's Chan School of Public Health.

If it doesnthappen in the summer, wed all be very surprised if we dont see some reemergence in the fall, he said.

Fact check: Sunlight does not kill the new coronavirus

In that case, COVID-19s sweet spotcould be the same as influenza, roughly October to May, with a peak between October and November, modeling suggests. If it does behave like influenza, it will move to the Southern hemisphere for winter there, then return to the Northern hemisphere for its cold months.

To anthropomorphize, the virus will come back here looking for new victims, Poland said.

The first wave of the disease, which the world isexperiencingnow, hit so hard because no one had immunity. It could eventually fall into a pattern ofyearly reoccurrence, like influenza.

If compounded with the annual wave of winter flu, the nations hospitals would be further taxed.

A fall spike also seems likely as children go back to school, said Mike Reid, a professor of infectious disease at the University of California-San Francisco.

To preventthat, wide-scale testing will need to be available, and contact tracing must be in place tofind everyone who hasbeen exposed and get them to self-isolate for at least 14 days.

Given the potential for repeated waves, the more that can be put in place to rapidly jump on every new spike and ring-fence every infected individual with wraparound health services is going to be crucial, Reid said.

When will life return to normal?Expert says US testing is too far behind to know

Experts say how we behave will play a large part in the size and severity ofsubsequent waves. People can help by remaining vigilant about washing their hands, continuingto socially distance and wear masks in public.

Add to that more surveillance andwidely available tests, chances improvethe second waveis smaller than the first.

As states begin to ease restrictions, theUnited States will effectively become a massive series of experiments.Epidemiologists will be watching carefully, Lipsitch said.

Some areas will reopen schools, while otherwill have staggered school days, so not all students are thereat the same time. The same will happen inworkplaces,even as more workfrom home. Some areas will cocoon the elderly, taking special care they are not exposed. Others may create passports for people who are immune, if there's data showing infectionconfers immunity.

There are many things we can do, and we dont know how any of them will work yet, Lipsitch said.

Doing temperature testing in schools and businesses,as is now done in Asia, could be helpful.

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

Staying Apart, Together: This newsletter will help you cope with the coronavirus pandemic

Vigilance will be key, experts say.

No one can say when the coast is clear, said William Hanage, a professor of epidemiology at Harvards Chan School of Public Health.

COVID-19 is easy enough to spread and has a long enough incubation period its possible to go from 100 known cases one week to 65,000 a few weeks later. One slip and we couldsee it resurging, he said.

Theres a cautionary tale from the 2003 outbreak of SARS in Toronto, which infected 375 people there and killed44. The city tookexpanded precautions beginning in March, but they were lifted in Maywhen it appeared theoutbreak was over. It wasnt.

Toronto took the brakes off," Hanage said. "Theyhad a flare, and it took them weeks to get it back under control.

Contact reporter Elizabeth Weise at eweise@usatoday.com

The former leader of the Global Rapid Response Team at the Centers for Disease Control and Prevention on Friday explained what we know about the COVID-19 pandemic. (April 10) AP Domestic

Read or Share this story: https://www.usatoday.com/story/news/health/2020/04/19/coronavirus-herd-immunity-vaccines-determine-covid-second-wave/5151957002/

Continue reading here:

When will a second wave of the coronavirus hit, and what will it look like? - USA TODAY