This winter is shaping up to be a wild one: Respiratory syncytial virus (RSV) is surging in young children, the flu ramped up early in many parts of the country, and chances are you or someone you know has already suffered through an especially nasty cold, according to recent data from the Centers for Disease Control and Prevention (CDC).
Many of the respiratory viruses that were in a bit of a lull over the past two years seem to be coming back in full force—and experts say we may have an “immunity gap” to blame for that.
An immunity gap can develop when your immune system essentially gets a break from being exposed to a mix of common pathogens—bacteria, viruses, and other microorganisms that can cause illness—in your environment, Aimee Bernard, PhD, an assistant professor in the department of immunology and microbiology at the University of Colorado Anschutz Medical Campus, tells SELF.
When you’re out and about—say, going to school, work, the gym, or restaurants—you come in contact with all types of pathogens that generally help keep your immune system on high alert and ready to protect you from infectious diseases.
But during the height of the pandemic, much of the country took critical public health precautions—like masking, social distancing, and working and studying remotely, among others—to help slow the spread of the virus that causes COVID-19. It makes sense, then, that our immune systems had less exposure to other infectious pathogens in recent years too, and therefore are slightly less prepared to take them on now, as they start to circulate widely.
That’s one possible reason why many respiratory viruses are surging atypically right now, Dr. Bernard says. She likens an immunity gap to the “hygiene hypothesis,” which posits that overly-sterile environments (a.k.a., super clean) “fail to provide the necessary exposure to germs required to ‘educate’ the immune system so it can learn to launch its defense responses,” as the US Food and Drug Administration notes.
What, specifically, all of this might mean for this year’s cold and flu season has yet to be seen, but Dr. Bernard believes it’s possible that the country is going to experience a stronger uptick in hospitalizations related to infectious diseases than usual. Some areas are already seeing this unfold: Connecticut Children’s Medical Center, for example, confirmed its pediatric unit is so overwhelmed with RSV and other respiratory illnesses, it’s considering working with the National Guard and FEMA to potentially set up a field tent to handle the swell of patients. (If you’re taking care of a young child, here’s more information about how RSV can affect kids.)
Who will be most affected by immunity gaps is a bit less clear, mainly because immunity gaps in specific groups of people haven’t been closely studied, since there hasn’t been a global pandemic in recent history. Experts know that we develop an immune “memory” of sorts after being infected with influenza, for instance, which can help soften the blow of future infections—so many people are likely more vulnerable right now due to the historically quiet 2020 and 2021 flu seasons. According to Dr. Bernard, older people—whose immune systems already aren’t quite as robust—may be even more susceptible to these infections. It’s not entirely understood whether an immunity gap would impact other immunocompromised individuals, like those with underlying conditions, since their risk is already higher than people who are otherwise healthy.