As the nation suffered a devastating winter wave of coronavirus cases, the phones at Old Dominion Pediatrics in Virginia rang. Callers with infected family members sought advice on how to quarantine at home so that others would not get sick.
But no one asked about the flu.
And the test results Eric Freeman saw showed that dozens of his patients had coronavirus, but almost none tested positive for the flu.
“COVID has just been the dominant viral pathogen at the moment and has not really allowed the flu enough space to populate itself properly,” Freeman said in an interview Monday. “I didn’t have a quick positive flu test in my office before Thanksgiving.”
Public health experts, GPs and pediatricians have warned for months that an increase in coronavirus cases in the winter months would be exacerbated by a typical flu season, which kills tens of thousands of Americans each year. But one funny thing happened in the middle 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 tested positive for the flu virus this year, between clinical lab results and public health labs. So far last year, more than 290,000 people tested positive for the flu.
The CDC reported in August that 198 children had died from flu in the last flu season, a record. So far this year, only one child has died, the lowest number since records began to be kept in 2004.
“You would never think there would be a silver lining in this regard [pandemic]”But this is about as close to a silver lining as it has been,” said Peter Hotez, a pediatrician and dean at Baylor College’s National School of Tropical Medicine. “This is what masks and social distancing wear, and it has probably reduced classes in person. [does]. ”
Less than 1 in 1,000 hospitalizations this year were for the flu, a quarter of the proportion recorded in the last flu season with low severity in 2011-2012.
American health officials and vaccinologists usually gather key clues about the flu season coming from viruses that start circulating in the winter months in the southern hemisphere, our summer months.
But even though these officials sounded the alarm about the potential for a double season of respiratory illness, the governments of Australia, Chile and South Africa reported less than normal flu circulation. Viral curves in these three countries have started to decline much faster than in previous seasons, as new blockages and restrictions have been put in place.
“In the last twelve months, except for some countries in West Africa and some countries in Southeast Asia, no one has had a flu season. And this is in countries that are closing really tight, it’s in countries that may not have closed as strictly. That confuses me a little bit, “said Richard Webby, director of the World Health Organization (WHO) Collaborating Center for Animal and Bird Influenza Ecology Studies at St. Jude Children’s Research Hospital.
The same thing seems to be happening in the United States. The flu is less transmissible than the SARS-CoV-2 virus that causes COVID-19, which means that masks and social distancing have an even greater impact on the total number of flu cases than on the coronavirus. The closure of the school meant the reduction of one of the most prolific vectors of person-to-person transmission.
“Toddlers and schools are pretty important players when it comes to spreading the flu in the community,” Webby said. “With many schools not being open or control measures actually being in schools, this has had a major impact on flu outbreaks.”
And, Freeman said, parents have heeded warnings from public health officials that their children should be vaccinated against the flu. 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, have been substantially higher than in previous years.
“This was one of the best years I’ve had in 15 years of flu vaccination. This year, the parents were definitely engaged, very enthusiastic, “said Freeman. “It was a point where I couldn’t keep the flu shots on my shelves.”
It seems that nothing about the coronavirus pandemic has not been easy and some experts have warned that even the least harmful flu season could have some disadvantages. A typical flu season provides clues about the strain that will become dominant next year, giving vaccine manufacturers the ability to adapt next year’s shots 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 Institute of Health and Agents at the Icahn School of Medicine in Mount Sinai. Because there is such a low circulation of influenza, we do not know exactly what strains, what 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 CDC’s Influenza Division of Virology, Surveillance and Diagnosis, said the WHO Global Influenza Surveillance and Response System is still testing between 50,000 and 100,000 samples a week to identify dominant strains.
“The low number of positive specimens has 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 for influenza season 2021-22, but it should be noted that the virus selection and recommendation process The vaccine 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-vaccination serological studies to show which strains could break out next year, prognosis models and vaccine efficacy studies.
The lack of an increase in influenza infections has reduced what could have been a disabling health pandemic at the height of the pandemic, when more than 100,000 Americans were treated for COVID-19 in hospitals across the country. And the United States still has a large number of deaths caused by what the CDC calls flu-like illness – although in this case the vast majority is due to COVID-19.
The flu will not go away, and health officials are constantly monitoring the worrying strains that could become the next threat to human health – WHO said in January it was pursuing an outbreak of H5N6 in China, cases of H1N1 in China and the Netherlands, H1N2 in Brazil and H3N2 in a child from Wisconsin.
But, doctors hope, the success of maintaining the flu this year will lead to greater acceptance of the vaccine that occurs in late summer and early fall.
“These [mitigation] the measures really work to reduce the spread of respiratory infectious viruses, ”said Garcia-Sastre. “I don’t think we’ll reduce the cases enough to completely prevent the virus from spreading.”