Food allergy is associated with lower risk of SARS-CoV-2 infection

When the HEROS study began, preliminary evidence from other research suggested that having an allergic disease might reduce a person’s susceptibility to SARS-CoV-2 infection. The HEROS investigators found that having self-reported, physician-diagnosed food allergy cut the risk of infection in half, but asthma and the other allergic conditions monitored—eczema and allergic rhinitis—were not associated with reduced infection risk. However, the participants who reported having food allergy were allergic to three times as many allergens as the participants who did not report having food allergy.

Since all these conditions were self-reported, the HEROS study team analyzed the levels of immunoglobulin E (IgE)-specific antibodies, which play a key role in allergic disease, in blood collected from a subset of participants. A correspondence between self-reported food allergy and food allergen-specific IgE measurements supports the accuracy of self-reported food allergy among HEROS participants, according to the investigators.

Dr. Hartert and colleagues speculate that type 2 inflammation, a characteristic of allergic conditions, may reduce levels of a protein called the ACE2 receptor on the surface of airway cells. SARS-CoV-2 uses this receptor to enter cells, so its scarcity could limit the virus’s ability to infect them. Differences in risk behaviors among people with food allergy, such as eating out at restaurants less often, also could explain the lower infection risk for this group. However, through biweekly assessments, the study team found that households with food-allergic participants had only slightly lower levels of community exposure than other households.

Interesting, and I hope this correlation leads to treatment or prevention measures for the general population down the line. As an anecdote, I have a food allergy and to my knowledge have not contracted the virus.


I also have a food allergy and haven’t had covid that I know of. If true it would be the first thing to ever be positive about my tendency to break out into hives when exposed to even trace amounts of basil.

I have multiple food allergies and I’ve had covid twice. So it’s not an absolute rule.

I also work at a job with a LOT of exposure to the public, so that’s a factor.

I’m sure it’s not a direct causation, which means there’s some other factor that’s actually relevant. Which naturally leads one to wonder what other factors they controlled for. For instance, are food allergies (or at least, diagnosed food allergies) more common among the more well-to-do? If that’s what it is, then it’s old news, because it’s been known for a while (and no surprise) that poverty is a risk factor for covid.

Last paragraph about the ACE2 receptor? Seems like a plausible direct mechanism. It’s the entry point for the virus, and it’s part of an inflammation regulatory pathway.

It could depend upon what food you’re allergic to. The article didn’t identify any specific foods.

Ah, I skimmed over that. Yeah, I can see how that could be relevant.