BETHESDA, Md. — Food allergies can be a real annoyance and constant concern for people, especially when they’re eating out. However, a new study finds being allergic to things like peanuts or shellfish may be keeping many people safe from COVID-19.
Researchers with the National Institutes of Health have found that having a food allergy can cut the risk of contracting coronavirus in half. However, having asthma or other allergic conditions such as eczema and allergic rhinitis did not lower the risk of infection.
The same report, part of the Human Epidemiology and Response to SARS-CoV-2 (HEROS) study, also found that children under 12 are just as likely to contract COVID-19 as teens and adults. Despite that, three in four children with COVID are asymptomatic.
“The HEROS study findings underscore the importance of vaccinating children and implementing other public health measures to prevent them from becoming infected with SARS-CoV-2, thus protecting both children and vulnerable members of their household from the virus,” says Dr. Anthony Fauci, director of the National Institute of Allergy, and Infectious Diseases (NIAID), in a media release. “Furthermore, the observed association between food allergy and the risk of infection with SARS-CoV-2, as well as between body-mass index and this risk, merit further investigation.”
More sneezes, more protection
The HEROS study monitored over 4,000 people living in 1,400 households which had at least one person under the age of 21 living there during the pandemic. The study took place in 12 different U.S. cities between May 2020 and February 2021, before the widespread rollout of the coronavirus vaccine.
The team notes that approximately half of the volunteers had a self-reported case of asthma, eczema, allergic rhinitis, or a food allergy. One caregiver in each house took COVID nasal swabs from everyone in their home every two weeks. Each participant also filled out a weekly survey, detailing their health and daily activities. Additionally, researchers collected blood samples periodically and after a family’s first positive test for COVID-19.
Like previous studies examining the link between allergies and a lower risk of coronavirus infection, the HEROS study found participants with a doctor-diagnosed food allergy were half as likely to contract the virus. People with asthma and other conditions, however, did not see a lower infection rate.
The team also notes that people with a food allergy were allergic to three times as many allergens as people without a food-related allergy problem.
Allergies actually protect the cells from COVID
To track down what’s protecting people with food allergies, the study authors analyzed each person’s levels of immunoglobulin E (IgE)-specific antibodies. These play a major role in the development of allergies. Again, the team found a link between an allergy sufferer’s self-reported symptoms and food allergen-specific IgE levels in their blood.
With that in mind, the team suspects that type 2 inflammation lowers the amount of a protein called the ACE2 receptor on the surface of human cells. This type of inflammation is a key characteristic in allergic reactions. Moreover, the ACE2 receptor plays a pivotal role in COVID infections. Virus cells attach to this particular protein to gain access to a patient’s cell functions — creating more of the virus and making patients even sicker.
Since allergies appear to wipe out a large portion of the ACE2 receptors on cells, study authors say this makes it much harder for the virus to spread through an allergy sufferer’s body.
Researchers also noted a slight difference in the behavior of people with food allergies. These individuals generally go out to restaurants slightly less than a person with no allergies — and no concerns about what’s on the menu. This also gives them a slightly lower chance of coming into contact with someone who has COVID-19.
Weight continues to be a COVID risk factor
In addition to the findings on allergies and children, the study also found more evidence linking obesity to a higher risk of infection. Both being overweight and having a higher body mass index (BMI) contributed to an increasing risk of SARS-CoV-2 infection.
For every 10-point increase in BMI, a person’s risk of infection increased by nine percent. Participants who were overweight or obese had a 41-percent higher risk of infection than those with a healthy weight.
NIAID sponsored and funded the HEROS study.
These findings appear in the Journal of Allergy and Clinical Immunology.