Influenza Season 2020-2021: It didn’t happen. Can this be repeated next season?

The sum of all our mask wear, distance, business closures, and other but incomplete precautions wasn’t enough to get the Covid-19 pandemic on track.But there is a silver lining: it have This season was enough to virtually wipe out the flu.

As of January 30, according to the Centers for Disease Control and Prevention (CDC) It was only 1,316 Influenza-positive cases in the clinical surveillance network since September. Around this time last year It recorded 129,997 positives Cases of influenza in the same time frame.

Part of the decline may be because people have not been tested for the flu or because they are at home for fear that their symptoms may be a Covid-19 infection. However, researchers believe that the decline in actual cases is realistic and rapid.

It’s not just the confirmed cases that are down. CDC Syndrome Surveillance System — Attempts to Track Disease Based on People Appearing in Symptomatic Clinics — Historically shows low levels of influenza..

Tim Ryan Williams / Vox

CDC last year’s flu season Estimated The virus was responsible for “38 million illnesses, 18 million consultations, 405,000 hospitalizations and 22,000 deaths.”

This year’s flu trend means “we have found a way to reduce the deaths of tens of thousands of people each year.” Cima camel, Says an influenza researcher at the University of Pittsburgh.

This news includes both silver lining and warnings.

Fortunately, we have seen how effective our collective action is in reducing the burden of influenza. And thanks to this experience, we may be ready to put the death toll of a future influenza pandemic on its orbit.

Warning: We haven’t had the flu this year, so more people will be more likely to get the flu next year. Children are particularly vulnerable to the flu, and next year there will be more children who have never had the flu. This will also increase their chances of spreading it. Some adults may also be more susceptible to the flu next year. The immunological memory of the virus fades over time, and by the time the next flu season begins, many adults will be one year after their last flu shot.

You need to remember some of what you learned during the pandemic to reduce the overall burden of the upcoming flu season. Even after the pandemic has declined, not all Covid-19 precautions can be maintained. However, you need to carefully consider what changes you should make.

There was no flu season

This flu season is more or less unrealistic. Not a surprise at all. During last year’s Southern Hemisphere flu season (occurs in the Northern Hemisphere summer— May to September) The number of cases and deaths also decreased..

That said, researchers didn’t take it for granted that the flu wouldn’t spread this winter.

“Until a few weeks ago, we still didn’t feel like we were out of the forest.” Schweta BansalSays epidemiologists and biologists at Georgetown University. But now it’s February, when the flu season usually peaks in the United States. She feels like the flu wave isn’t coming. And it’s not just the flu. Other respiratory viruses except rhinovirus Also fell dramatically..

This is a great relief. In the early days of the pandemic, scientists were very worried. About the burden on our medical system If the flu was circulating on a large scale with Covid-19. The quiet flu season means that Covid-19 patients have more beds and equipment available, and the healthcare professionals who treat these patients are less burdened than in a normal flu year.

Researchers do not attribute the sharp decline this year to an increase in the number of people vaccinated against the flu. “Vaccinations have helped, but there is absolutely no way this can be caused by increased vaccinations alone.” Stephen Kistler, Says Harvard epidemiologists. Yes, the intake of influenza vaccine is increasing (Approximately 15.5 million additional doses), But it’s not enough to explain what happened to the flu. (Influenza spreads more commonly from contaminated surfaces, so regular surface cleaning can be a sanitary theater When it comes to Covid-19, But it may help when it comes to the flu. )

What is your responsibility? “As far as I know, the most consistent explanation is that wearing a mask and keeping a distance actually did that,” says Kistler.

Why the flu was defeated but Covid-19 wasn’t defeated

How can I stop the flu by wearing a mask and keeping a distance while the Covid-19 is rampant?

It goes back to what scientists said at the beginning of the pandemic: Covid-19 Method, much worse than seasonal flu Because it is more contagious.

Scientists describe the contagiousness of the disease with a number called R0 (pronounced r-naught). On average, this number represents the number of new cases in which each case of the disease continues to occur. For seasonal influenza, R0 is between 1 and 2. For Covid-19, it’s likely to be between 2 and 3, if not a little higher.

Due to our collective action, the effective R number of Covid-19 has dropped to just over 1. As long as the R number is greater than 1, the virus will continue to spread. But when it comes to influenza, all that collective action has certainly reduced the effective R of influenza to less than one.

For Kistler, this is textbook epidemiology. [than Covid], But it spreads in a similar way, well below the R threshold of 1, which is only wiped out. “

It feels good that our efforts have wiped out the flu. One less burden to deal with already difficult years. However, there are some optimistic views for the future. Let’s say you have another pandemic respiratory virus. However, it is a bit less contagious than Covid-19. If we can contain the new virus with the same collective action power as we do now, the pandemic will probably be stopped.

Learn more about influenza infection when society returns to normal

Scientists do not know exactly which Covid-19 public health procedure contributes most to reducing influenza cases. But they are suspicious. “The biggest differences are lack of travel, school closures, distance and masking,” he says. Helen Chu, A doctor and epidemiologist at the University of Washington studying influenza.

It’s hard to say clearly which one contributes the most. “Influenza can disproportionately ill children and put them in hospitals, so school closures and the like have a greater impact on influenza than SARS-CoV-2,” says Chu.

But then, “I can’t imagine school closures doing most of it, because you can keep schools open in so many places, such as Australia, and you haven’t got the flu yet. They still kept the school open and there was no flu. ”

Scientists currently don’t know how much each intervention has contributed to this year’s flu reduction, but they think they have the opportunity to learn more.

“There are so many regional differences in masking, increasing social distance, and closing schools, so I hope someone will see this across the United States and make fun of it state by state,” Chu said. Says. Perhaps these differences in policy and behavior can be correlated with the consequences of a cold or flu to better understand what worked.

One of the more helpful: scientists monitor what happens when Covid-19 precautions are lifted. “We will be able to see the circulation of influenza and other respiratory viruses,” says Kissler.

Therefore, scientists can potentially see which restrictions and behavioral changes lead to a higher recovery of the respiratory virus.

You can reduce the burden of seasonal influenza without being blocked

You can use a pandemic to think about how society will change in the future to prevent these infections and deaths. “The seasonal flu virus remains a major public health burden,” says Rakdawara. It’s still true after the pandemic is over, and we need to remember some lessons from the pandemic to deal with it.

For example, if you had been exposed to someone who had the flu or a cold in the past, you wouldn’t have thought about anything. In the future, I would like to consider not going to the office with friends after the pandemic or after exposure (influenza has a shorter incubation period than Covid-19 and does not need to be quarantined. Probably up to 4 days).. And be sure to wear a mask in public when you are sick or after being exposed to a virus. Influenza like Covid-19 No symptoms And people can infect others before they feel sick..

You may be more cautious during the flu season and want to wear a mask around others. “I think wearing a mask in the winter is something that might stay here,” says Kistler. Overall, there should be more acceptance of wearing masks in public places. That way, you’re less likely to attract eyes and confusion.

In the future, employers and employees may be able to better understand the importance of staying at home and take sick leave when infected with the virus.

“We have a lot of research that we asked people.” Did you stay home because you got the flu? And they will say “no”, “says Chu. “We think it’s important to come to work, and we think staying home when you’re sick is a sign of weakness. I think it’s going to change altogether.” In addition, parents caring for their children with the flu should be given the time and resources to stay at home. That way, they won’t spread it to others.

Schools can also use distance learning more wisely. If the district becomes aware of an outbreak of influenza in school, it can temporarily move to distance learning to avoid a major outbreak in the community.

All of these actions should be done in addition to ensuring that as many people as possible are vaccinated against the flu. Shots are usually 40-60% effect Even if everyone is vaccinated each year (and usually only about half of Americans are vaccinated) to prevent someone from developing the flu symptoms, we still have new lessons learned. Should be incorporated.

You need to be vigilant for the next flu season

There is no need to blockade to mitigate the future flu season. During the typical flu season, the burden is too great and unnecessarily excessive.

However, it still requires a great deal of caution, especially during the next flu season. Scientists do not know exactly how influenza will evolve in response to this strange new environment.

“We don’t know how eradicating the flu for a year will affect the evolution of the flu,” says Kistler. This can make it difficult for vaccine developers to choose the right strain for next year’s vaccine. “I don’t know if next year’s flu strains will be so widespread that it will be easier to predict, or if this becomes very difficult, we are experiencing a very difficult situation called an evolutionary bottleneck. Because. “

Here’s what we know: We can defeat the flu with our own actions. Covid-19, in part, “showed us how to do that,” says Kissler.