A study funded by the National Institutes of Health (NIH) in the United States has found people with food allergies are less likely to become infected with SARS-CoV-2, the virus that causes COVID-19, than people who don’t have them.
The Human Epidemiology and Response to SARS-CoV-2 (HEROS) study followed more than 4,000 people in nearly 1,400 households throughout the US, and along with food allergies, it looked at the effects of obesity, high body mass index (BMI), asthma, and how the virus affects children under the age of 12.
The researchers found those who had a self-reported, doctor-diagnosed food allergy had a 50 per cent lower risk of getting infected with coronavirus than those without food allergies.
It was hypothesised that people with food allergies may have a lower risk of catching the virus because they tend to dine out less than the general population, but the researchers found that households with food-allergic participants had only slightly lower levels of community exposure than other households.
An alternative hypothesis has been proposed that a “type 2 inflammation” which is characteristic of allergic conditions, could reduce levels of a protein called the ACE2 receptor on the surface of airway cells. Coronavirus uses this receptor to enter cells, so its scarcity could limit the virus’s ability to infect them.
Unlike for those with food allergies, the HEROS study didn’t find that people with allergic asthma had a reduced risk of coronavirus infection, but asthma did not appear to increase the risk of infection. The study confirmed previous findings that obesity or a high BMI presents an increased risk factor for COVID-19 infection.
The observed association between food allergy and the risk of COVID-19 infection merit further investigation.