June 03, 2022
People walk past a COVID-19 testing site on May 17 in New York City when New York’s health commissioner, Dr. Ashwin Vasan moved the alert level from "medium" to "high" in all five boroughs. A recent National Institutes of Health study found that food allergies reduced COVID risks by 50 percent. (Spencer Platt/Getty Images)
Food allergies are actually a good thing when it comes to the risk of contracting COVID-19, according to a new study funded by the National Institutes of Health (NIH).
The Human Epidemiology and Response to SARS-CoV-2 (HEROS) study was published in May in the Journal of Allergy and Clinical Immunology and reported that a self-reported doctor-diagnosed food allergy was associated with a 50-percent lower infection risk.
The initial intent of the study was to determine whether self-reported asthma and/or other allergic diseases are associated with SARS-CoV-2 infection and household transmission. It was reported that doctor-diagnosed asthma was not a risk factor for infection, nor was upper respiratory allergy or eczema.
...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.-NIH
"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," Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), part of NIH, said in a statement. "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."
NIAID sponsored and funded the HEROS study.
The study followed COVID-19 infection in over 4,000 people in approximately 1,400 households that included at least one person aged 21 or younger. Individuals were monitored between May 2020 and February 2021 across 12 cities in the United States, prior to the rollout of vaccines to the general public.
A caregiver in each household took nasal swabs of participants every two weeks to test for COVID-19, involving the filling out of weekly surveys. If symptoms were consistent with COVID-19, additional swabs were required. Blood samples also were collected periodically if necessary.
The NIH said study participants were recruited from existing, NIH-funded studies focused on allergic diseases—including nearly 50 percent of participating children, teenagers and adults who had a self-reported food allergy, asthma, eczema, or allergic rhinitis.
Dr. Max Seibold is a professor of pediatrics in the Center for Genes, Environment, and Health at National Jewish Health in Denver, Colorado. He told Newsweek NIAID contacted him in March 2020 to contribute to the study.
"There was a lot of uncertainty as it pertains to the risk involved for people with asthma, and also susceptibility among children with asthma and how transmission might work within families," Seibold said.
There was a lot of uncertainty as it pertains to the risk involved for people with asthma, and also susceptibility among children with asthma and how transmission might work within families.-Dr. Max Seibold
Being an NIH-funded researcher, Seibold said he already had cohorts of children with asthma or allergies. He and other re-recruited subjects into the HEROS study to undergo surveillance for about a seven-month period.
His lab, the Seibold Lab, does a lot of airway transcriptomics that includes nasal sampling to better understand asthma airways. His lab was contacted to process and test for COVID-19, running epidemiological analyses of generated data—involving running several studies on viral infections.
"It's not a finding that we necessarily expected, or at this point have the answer to the ideology of the observation," Seibold said regarding the link between food allergies and a much-reduced rate of infection risk.
He said a study in 2020 looked at inflammation patterns and the nasal airways of children, finding that those with higher inflammation—or Type 2 inflammation—expressed lower levels of an ACE2 receptor gene that routinely binds and gains entry into cells to start an infection.
Dr. Tina Hartert, director of the Center for Asthma and Environmental Sciences Research and a professor of medicine and pediatrics at the Vanderbilt University School of Medicine in Nashville, Tennessee, co-led research with Seibold.
"We had speculated that asthma and allergic diseases might decrease risk of infection based on findings that there are fewer receptors (ACE2 receptor) for SARS-CoV-2 on the surface of cells in the airway in those with certain types of inflammation seen with allergy," Hartert told Newsweek. "This should mean that fewer viruses would be able to get inside of airway cells in those with asthma and allergies. However, we only saw lower risk of infection among those with food allergy."
There were conclusions beyond food allergies and asthma, too, including the finding that children play a critical role as a reservoir of asymptomatic infection and household transmission. Seibold and Hartert said that about 75 percent of infections in children were asymptomatic, and as Hartert said, attending in-person school "was the greatest risk factor for introducing infection into a household."
"There was even more circulation of the virus than was recognized because of how much asymptomatic infection was occurring, especially among young individuals," Seibold added.
The study also showed that an increasing body mass index (BMI) was associated with an increased risk of infection. Essentially, the higher the BMI, the higher the risk of infection as Hartert described.
Seibold said doctors have long known that obesity is a risk factor for severe COVID-related, but this study "found that obese or more overweight individuals are more likely to be affected" due to a linear relationship between BMI, or a fat composition increase, and an infection increase.
Confirming the findings and identifying the mechanisms for the decreased risk of infection among those with food allergy and increased risk with BMI could be very interesting in identifying strategies to prevent the establishment of infection.-Dr. Tina Hartert
Hartert said the entirely remote study involved "remarkable" participating households, " in that they were both study participants and their own research team"—including collecting their own samples from noses before infection, during infection, and after infection.
"Confirming the findings and identifying the mechanisms for the decreased risk of infection among those with food allergy and increased risk with BMI could be very interesting in identifying strategies to prevent the establishment of infection," she said.
A study, with research conducted at the University of Kansas, found that "conversion messages" were quite effective in encouraging hesitant individuals to get vaccinated.