Fear of a “perfect storm” as the flu season approaches

Ask an infectious disease expert about this season of influenza and how COVID-19 will or will be affected. The word you can hear is “uncertainty”.

For starters, they will say that the flu is always unpredictable. The activity and severity of influenza is highly dependent on the circulating virus strains and depends on how well the vaccine strains selected prior to each influenza season match the circulating strains.

“Sometimes it works, sometimes it doesn’t,” Jeanne Marazzo, MD, director of infectious diseases at the University of Alabama at Birmingham, recently told the American Society for Infectious Diseases (IDSA). )briefing.

The pathogenicity of circulating strains, the dynamics of transmission, existing herd immunity, and the most vulnerable age group also affect the number of people affected by influenza each year. Centers for Disease Control and Prevention since 2010 Estimate Influenza affects 9 to 45 million people annually, and last year about 39 million people were infected with the flu.

But in this pandemic year, the coronavirus pandemic adds a whole new and unpredictable layer.

Two scenarios emerge

“Of course, this year’s big concern could be the perfect storm of accelerated COVID-19 activity, especially as people continue to get socially tired, especially wearing masks, as more people gather inside. See if it’s because of distance, hand hygiene, and exposure to seasonal flu. “

The “complete storm” could reach capacity in hospitals across the United States as both influenza patients and patients infected with SARS-CoV-2 (the virus that causes COVID-19) seek treatment. .. It is a scenario written earlier this year by Dr. Michael Osterholm, Director of Infectious Diseases Research and Policy, MPH, and Dr. Ed Belongia, MD, Director of Clinical Epidemiology and Group Health Center at the Marshfield Clinic Institute. editorial for Science.

“Most of the population remains susceptible to SARS-CoV-2, and if the COVID-19 and influenza epidemics peak at the same time, hospital stress will be greatest.” They wrote.

However, in some scenarios, efforts being made to mitigate the spread of the coronavirus (physical distance, masking, improved hand hygiene, etc.) can help prevent influenza.

“There are a lot of variables and they can go in different directions,” MD, an infectious disease specialist at the Mayo Clinic in Rochester, Minnesota, told CIDRAP News.

The second scenario may explain the low number of influenza cases reported in countries in the Southern Hemisphere. The flu season begins in April and ends in September.

Australian Government Latest Influenza Surveillance Report, Influenza and influenza-like activity (ILI) are below average on all systems and the number of cases confirmed in the lab is small, so influenza has “minimal social impact”. South African health officials say the country has basically skipped the flu season. South American countries, including Brazil, Chile and Argentina, Reported everything The number of influenza cases is lower than usual.

Leonardo Melmel, DO, ScM, a professor of medicine at Brown University, told IDSA, “I can only imagine that what we are doing to reduce the risk of infection with COVID-19 involves a significant amount of reduction. I can’t. “Briefing. “Masking, staying at home, avoiding crowds, being unable to work when sick, and suppressing some of what’s happening with COVID-19. Risk of influenza infection.”

But “we can’t pin all our hopes,” Melmel said, as Americans may not be as vigilant about physical distance and masking as people in those countries.

“There is variable acceptance of communities of these practices between and within this country,” Tosh said.

Tosh noted that the number of influenza in the United States, especially hospitalizations, dropped dramatically at the end of the 2019-20 influenza season, as well as the significant increase in coronavirus cases. .. But that was because people avoided going to emergency departments and emergency clinics, and maybe not because of the actual reduction in infections.

Testing concerns

If the country’s influenza activity is above typical levels this season and is accompanied by a surge in COVID-19 cases, one of the concerns is the testing capacity and supply (cotton swabs and reagents) that have already been tested. Etc. Pandemics can be overwhelming.

As Mermel pointed out, the symptoms of influenza and COVID-19 are very similar, with the exception of anosmia (loss or loss of smell). This means that clinicians may need to test for both influenza and SARS-CoV-2.

If the flu is very prevalent during the typical flu season, Tosh explained that flu testing is primarily for people who are severely ill or need hospitalization. But this season, for both therapeutic and epidemiological reasons, clinicians and public health professionals need to know who is infected with the flu and who is infected with the coronavirus.

“We think someone needs to test for both COVID and flu. If they are presenting to healthcare with a flu-like illness, of course, supply chain issues related to COVID testing. Complicates things in that there is already. ” “I think this could exacerbate the supply chain that is already stressed by both influenza and COVID testing.”

“My concern is that the system can quickly overwhelm, and individual clinicians face many challenges trying to figure out how to perform both of these tests in a timely manner. Let’s do it, “said Marazzo.

Mermel said his hospital is currently considering a platform that can perform rapid tests for both influenza and COVID-19.

“But if these tests are missing, problems will occur,” he said. “We certainly need to have a stockpile of reagents and kits, so that frontline people can distinguish between these two viruses, treat viruses that need flu treatment, and quarantine. COVID-19 can warn public health authorities. Contact tracking.

Influenza vaccination is more important than ever

Influenza vaccine maker in preparation for the next flu season Production increased In the United States, about 200 million doses reduced by 15%. Pharmacies and doctors’ offices have systems in place to keep physical distance. Regardless of how this year’s flu shot is prevalent, public health officials and infectious disease experts say this year’s flu shot will be very important.

“The flu vaccine works. It prevents hospitalization, it prevents death, and it prevents symptomatic illness,” Marazzo said. “If you have a year when you need to get your flu vaccine, let your child get the vaccine, because you really need all the protection you can get. This year. “

“It’s important to get it [the flu vaccine] Every year, but I can’t emphasize the importance of getting it this year [enough]”.

“It’s time to be at the forefront, get the vaccine, and reduce the risk of these two life-threatening viruses infecting you and your loved ones at the same time,” Melmel said.