As the nation suffered a devastating winter wave of coronavirus cases, Old Dominion Pediatrics phones in Virginia rang. People who called with infected family members asked for advice on ways to quarantine themselves at home so that others would not get sick.
But no one asked about the flu.
And the results of the test Eric Freeman saw showed that dozens of his patients had coronavirus, but almost none tested positive for the flu.
“COVID has just become the dominant viral pathogen at this time and has not really allowed the flu to have enough space to populate itself properly,” Freeman said in an interview Monday. “I haven’t had a quick positive flu test in my office since before Thanksgiving.”
Public health experts, general practitioners, and pediatricians had warned for months that an increase in coronavirus cases during the winter months would add to a typical flu season, which kills tens of thousands of Americans annually. But something funny happened in the midst of a global health pandemic: the flu season was effectively canceled.
Data from the Centers for Disease Control and Prevention (CDC) show that only 1,893 Americans have tested positive for the flu virus this year, among the results of the clinical lab and public health labs. At this point last year, more than 290,000 people had tested positive for the flu.
The CDC reported in August that 198 children had died from flu-related causes during the last flu season, a record high. So far this year, only one child has died, the lowest figure since records began in 2004.
“You would never think there would be a silver lining [pandemic]”But that’s almost as close to the silver lining as there used to be,” said Peter Hotez, a pediatrician and dean at Baylor College’s National School of Tropical Medicine. “That’s what masks and distancing do. social and probably reduces face-to-face classes [does]”.
Less than 1 in 1,000 hospitalizations this year have been from influenza, one-seventh of the proportion recorded in the last low-severity flu season in 2011-2012.
U.S. health care providers and vaccinators often collect key suggestions about the upcoming flu season from viruses that begin to circulate during the winter months in the southern hemisphere, our summer months.
But even as these officials sounded the alarm about the potential for a double season of respiratory illness, the governments of Australia, Chile and South Africa reported lower-than-normal flu circulation. Viral curves in these three countries began to decline much faster than in previous seasons, as new blockades and restrictions were established.
“During the last twelve months, with the exception of some countries in West Africa and some countries in Southeast Asia, no one had a flu season. And that’s in countries that close strictly, it’s in countries that may not have closed so strictly. That confuses me a bit, ”said Richard Webby, director of the World Health Organization (WHO) Center for the Study of the Ecology of Influenza in Animals and Birds at St. Jude Children’s Research Hospital. .
The same seems to be happening in the United States. Influenza is less transmissible than the SARS-CoV-2 virus that causes COVID-19, meaning that masks and social distancing are likely to have an even greater impact on the overall number of influenza cases than on coronavirus. School stoppage meant curbing one of the most prolific vectors of person-to-person transmission.
“Toddlers and schools are pretty important players when it comes to flu transmission to the community,” Webby said. “Because many schools are not open or control measures are being carried out in schools, this has had a major impact on flu outbreaks.”
And, according to Freeman, parents heeded warnings from public health officials that their children should receive a flu shot. Although final data on flu vaccine acceptance rates will not be known for months, Freeman said vaccine acceptance rates in his practice, just south of Richmond, Virginia, were substantially higher. higher than in previous years.
“This was one of the best years I have had in 15 years of flu vaccination. This year, the parents were definitely committed, very enthusiastic, ”said Freeman. “It was to a point that I couldn’t keep the flu shots on my shelves.”
It seems that nothing in the coronavirus pandemic has been easy, and some experts warned that even the least harmful flu season recorded could have some drawbacks. A typical flu season provides clues about the strain that will become dominant next year, giving vaccine manufacturers the opportunity to tailor next year’s vaccines to a specific strain. Without this knowledge, it may be more difficult to produce a vaccine that matches next year’s strain.
“There is not enough information about the virus circulating in the world,” said Adolfo Garcia-Sastre, director of the Global Health and Emerging Pathogens Institute at the Icahn School of Medicine in Mount Sinai. “Because there is so little flu circulation, we don’t know exactly which strains, which variants are circulating now. This creates problems with the development of the vaccine and whether it needs to be updated or not.
David Wentworth, head of the virology, surveillance and diagnosis branch of the CDC Influenza Division, said the WHO Global Influenza Surveillance and Response System is still testing between 50,000 and 100,000 samples per week for identify dominant strains.
“The reduction in the number of positive specimens made it more difficult to identify the optimal vaccine viruses for each of the four major groups of influenza viruses that are included in most influenza vaccines during the flu season. flu 2021-22, but it should be noted that the process of selecting and recommending the vaccine virus is not based solely on the flu viruses currently in circulation, ”Wentworth said in an email.
The identification of the next strain is also based on genetic sequencing of current strains, post-vaccine serological studies to show which strains could explode next year, prediction models, and vaccine efficacy studies.
The lack of an increase in influenza infections has reduced what could have been a paralyzing tension in the healthcare system at the height of the pandemic, when more than 100,000 Americans were treated for COVID-19 in hospitals. from all over the country. And the United States continues to record a large number of deaths caused by what the CDC calls flu-like illnesses, although in this case the overwhelming majority is due to COVID-19.
The flu will not go away and health officials are constantly monitoring worrying strains that could become the next threat to human health – the WHO said in January that it was watching an H5N6 outbreak in China, H1N1 cases in China and the Netherlands, H1N2 in Brazil and H3N2 in a child in Wisconsin.
But doctors hope the success of keeping the flu under control this year will make the vaccine that comes in late summer and early fall acceptable.
“These [mitigation] the measures are really working to reduce the spread of respiratory infectious viruses, “Garcia-Sastre said.” I don’t think we will reduce the cases enough to completely prevent the spread of the virus. ”