Can Having COVID Multiple Times Make You More Susceptible to Other Infections?

There’s no doubt that, collectively, we’re exhausted from dealing with COVID-19 and the worry about new variants, including XBB. 1.5. Plus, the spike in flu and respiratory syncytial virus (RSV) cases this cold and flu season has people wondering if their immune systems are running on empty, too.

Here’s the thing: Yes, it is possible to get sick with multiple viruses at the same time. You can also catch colds and other illnesses shortly after recuperating from COVID. None of this is fun, especially if you’re trying to get back into the swing of “real life” after years of quarantine and social distancing. So, what’s going on? Could a diminished immune system or an altered COVID-19 virus be to blame?

We talked with an infectious disease doctor and a pulmonologist to get a sense of whether having COVID multiple times could weaken your immune system and make you more susceptible to other viruses or if we’re dealing with something else.

So, can having COVID multiple times weaken your immune system?

If you’ve been infected with COVID one or more times (and thousands of people have), you may be concerned about your ongoing vulnerability to other circulating diseases. If so, most experts say not to worry. Currently, there is no proven link between getting COVID-19 and long-term, increased susceptibility to other contagions, like viruses or bacterial infections. (However, having long COVID can increase your risk for serious health issues, according to new research.)

“An acute infection such as COVID and other viral infections, as well as many severe bacterial infections, can ‘occupy’ the immune system for a period of time. This may make you more vulnerable to a new infection that comes along. Although various COVID variants and sub-variants, as well as other pathogens, have ways of evading or combating our immune system’s defenses, there is no solid evidence that any lasting negative impact occurs with COVID,” says Charles Bailey, MD, medical director for infection prevention at Providence St. Joseph Hospital and Providence Mission Hospital in California.

In other words, there is nothing about COVID specifically that weakens your immune system or makes you more susceptible to other illnesses. So why does it seem like so many people are getting sick with all kinds of things this year?

This extended period of low exposure to normally circulating pathogens reduced herd immunity, generating the occurrence of what’s called an “immunity debt.”

COVID precautions reduced exposure to common circulating viruses

For several years, wearing masks and social distancing was necessary to protect the population from severe symptoms and dangerous complications like pneumonia and death. In addition to protecting people from COVID, taking these measures also kept other illnesses at bay in adults and children, including common colds, influenza, bronchiolitis, and RSV.

According to researchers in France, this extended period of low exposure to normally circulating pathogens reduced herd immunity, generating the occurrence of what’s called an “immunity debt.” Since this is not an established term in epidemiology, there has been some misunderstanding about what it actually means. Masking and social distancing did not weaken our immune systems—but they did temporarily reduce our exposure to these pathogens. As behaviors have changed, these pathogens have spread more readily. So, a more accurate term is actually “immunity gap.”

We’ve seen this immunity gap in action in the larger-than-normal population of babies and toddlers grappling with RSV infection this year.“Infants, of course, are born all the time and usually get infected with RSV by age 2. However, during the last two years of isolation and social distancing, many infectious respiratory diseases did not make their usual rounds, including influenza, RSV, and others. Because of this, there are many more opportunities this year for viruses to infect non-immune individuals,” explains Roger Seheult, MD, a pulmonologist and medical advisor to Intrivo, and assistant clinical professor at the School of Medicine and Allied Health at Loma Linda University in California.

“With little social distancing to stop the spread of viruses, those previously infected and immune to RSV, such as older children and adults, have not had the opportunity [for] exposure during the last two years. This has caused immunity to wane in a significant proportion of the population,” he says.

So, people who have never had certain viruses (read: babies and young children), and older people who haven’t had exposure in a couple of years are coming down with these viruses now—which is why it may seem like you or your loved ones are getting sick constantly.