Health experts are warning of a possible “twindemic” ahead of the upcoming flu season as COVID-19 spreads among communities and children return to classrooms.
“Based on what we are currently seeing for other respiratory infections … I expect we will see a resurgence of influenza at above-average levels this year,” said Dr. David Cennimo, an infectious disease specialist at Rutgers New Jersey Medical School.
The health experts’ projections run contrary to the experience of last year’s flu season, which saw hardly any activity as the pandemic led to shutdowns and students learned virtually, among other precautions.
Now people are going out again and children are back in classrooms as the pandemic drags on.
Children have the “distribution franchise” for flu and can spread the virus among themselves while at school and then bring it back to their families and communities, said Dr. William Schaffner, an infectious disease specialist at Vanderbilt University.
“Children are supposed to be the real disseminators,” he said. “When they get infected, they shed more flu virus than adults, and they shed the virus for longer periods of time.”
Dr. Schaffner stressed that the flu and COVID-19 are caused by two different viruses and that their vaccines do not protect against each other.
But companies like Novavax and Moderna are working to develop a single vaccine for the flu and COVID-19.
Dr. Schaffner said the spread of COVID-19 and influenza could be stressful on health care systems, which are already under strain with coronavirus cases, and could lead to more hospitalizations and deaths.
“It’s very hard to predict the severity of any flu season. However, it is almost certain that influenza will be back, since most Americans are no longer adhering to the strict infection control behaviors that were in place last flu season with COVID-19,” said Litjen Tan, chief strategy officer of Immunization Action Coalition.
Mr. Tan added that Australia saw the flu remain at “historically low levels” this past season but noted the continent is still practicing strict social distancing and masking requirements.
It’s tricky to compare the flu season in the U.S. based on what happened in Australia even before the COVID-19 pandemic, he added.
Although rare, it’s possible to contract the flu and COVID-19 at the same time, which could cause a “much worse condition,” said Dr. Cennimo.
“If you contract the flu, you will have to quarantine and be tested to rule out COVID-19. This highlights the importance of children under 12, who cannot yet receive the COVID-19 vaccine, receiving the flu vaccine,” Dr. Cennimo said. “Vaccinated children are less at risk for the flu, whose symptoms can be confused with COVID-19 and cause possibly unnecessary school quarantines while awaiting a proper diagnosis.”
The flu has sickened an estimated 9 million to 45 million people, hospitalized between 140,000 to 180,000 and killed 12,000 to 61,000 each year since 2010, the Centers for Disease Control and Prevention says.
This past flu season had “unusually low” activity, despite high levels of testing, the CDC says. Only 1,675 out of 818,939 respiratory specimens, or 0.2%, tested by labs came back positive for an influenza virus, compared to about 26% to 30% during the last three flu seasons before the pandemic, CDC data shows.
The most recent flu season had the lowest recorded hospitalizations and only one report of a child dying from the flu. Flu deaths in children ranged from a low of 37 between 2011 and 2012 to a high of 199 between 2019 and 2020.
The unusually low flu activity can be likely attributed to COVID-19 safety measures such as wearing face masks, school closures, reduced travel, physical distancing and increased ventilation of indoor spaces, the CDC says.
Flu activity typically begins to climb in October, with peaks between December and February, but can last as late as May.
The CDC recommends that everyone age 6 months and older receive a flu shot each year. People at higher risk of serious complications from the flu include people 65 years and older, those with chronic medical conditions such as diabetes or heart disease, pregnant people and children younger than 5 years old.
All flu shots this year are quadrivalent, according to Dr. Schaffner, meaning that they protect against four different flu viruses. This is the first year that all of these shots are quadrivalent, he noted, commenting on how manufacturers have been moving toward this goal for years.