May 26: MIT Medical answers your COVID-19 questions. Got a question about COVID-19? Send it to us at medical@mit.edu, and we’ll do our best to provide an answer.
I’ve been hearing people say that staying home and social distancing is harming our immune systems. The reasoning is that if we don’t come into contact with many germs, our immune systems weaken. This means that once we all start coming out of the house more, we’ll be more susceptible to colds and flu and even the new COVID-19 illness. Is this true?
We’ve been hearing this theory too, and we can assure you that this is NOT the way your immune system works.
Many people have heard of the “hygiene hypothesis” — the idea that individuals who are exposed to a variety of microbes (i.e., germs) in childhood build better immunity. In fact, there is evidence that young children who have early exposure to different types of germs are less likely to develop allergies and autoimmune disorders such as hay fever, asthma, or inflammatory bowel disease.
However, by the time you are an adult, you have already spent years being exposed to many types of bacteria and viruses. You’ve created a robust immune system that can respond to these microbes. Your immune system “remembers” viral and bacterial markers, and as soon as one of these markers shows up, your body starts making antibodies to destroy that intruder.
Of course, SARS-CoV-2, the virus that causes the COVID-19 illness, is a new virus. Before its initial appearance in humans at the end of 2019, no human had been exposed to the virus or had opportunity to build immunity against that particular pathogen. But while your immune system won’t have any specific “memory” of the virus, it will mount an immune response if you are infected — because that’s how your immune system works. Coming into contact with germs spurs an immune response, but it doesn’t do anything to make your immune system stronger. And this current period of contact with fewer germs does nothing to weaken the immune response you will be able to mount, as needed, in the future.
But that doesn’t mean social distancing will have no effect on your immune system. The psychological effects of social isolation can affect your immune system. The culprits are loneliness and stress.
Research shows that our anti-viral response is suppressed when we feel lonely. An analysis of 148 different studies involving more than 300,000 people found that people who were more socially connected were 50 percent less likely to die over a given period. One experiment even found that people with many social ties are less susceptible to the common cold.
Stress has similarly harmful effects on immune function, because the hormones involved in a stress response — cortisol, which stimulates the production of sugar, and epinephrine and norepinephrine, which increase heart rate and elevate blood pressure — interfere with the function of immune cells.
The pandemic has created different types of stress for all us, including the stress of having to socially distance ourselves for an extended period of time. So, work on staying in contact with the people you care about. Call, video chat, share photos and updates on social media, or find other ways to connect. And try to find ways to manage your stress. The Centers for Disease Control and Prevention (CDC) has some useful tips. And Community Wellness at MIT Medical offers a guided, three-minute relaxation recording at 617-253-CALM (2256) and free MP3 files you can download to practice mindfulness and relaxation on your own.
In addition to staying connected and controlling stress, other strategies for maintaining a healthy immune system include eating a balanced diet, exercising regularly, and getting enough sleep. Community Wellness at MIT Medical offers resources to help with these parts of your life as well — everything from information to virtual classes and free downloads.
While it’s unlikely that you’ll catch a cold the moment you start going out more, it will bring you into contact with more germs, and there’s a lot you can do to prepare that old immune system for those challenges. The pandemic has changed many things about our lives, but the road to good health is still paved with plenty of fruits and veggies, deep breaths, good friends, and a good night’s sleep.
