People with food allergies appear to be at lower risk of SARS-CoV-2 infection
Since the beginning of the pandemic, researchers have been trying to determine who is most at risk from SARS-CoV-2, and why.
Today, a new population study conducted by the National Institutes of Health (NIH) has highlighted a curious benefit of the coronavirus for people with allergies.
In an analysis of more than 4,000 people living in households with minors, researchers noted several curious trends in SARS-CoV-2 infection, including that people with food allergy were half as likely to be infected.
These findings are consistent with other recent research, which suggests allergic conditions, such as asthma, may offer some protection against severe cases of COVID-19.
Along the same lines, the new NIH study showed that asthma was not linked to an increased risk of SARS-CoV-2 infection, although asthma is a disease that affects the respiratory system.
In contrast, obesity and a high BMI index were factors that increased the risk of SARS-CoV-2 infection, as was the age of children and adolescents sharing the same living space.
But the food allergy finding might be the most remarkable finding.
“The observed association between food allergy and the risk of SARS-CoV-2 infection, as well as between body mass index and this risk, merits further investigation,” says Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases.
Researchers aren’t sure exactly why food allergies seem to make people less vulnerable to SARS-CoV-2, but there are a few possible explanations.
Half of the study participants said they had been diagnosed with food allergy, asthma, eczema or allergic rhinitis. These statements were later confirmed by a subset of blood tests, which revealed the presence of antibodies linked to allergic diseases.
The researchers then tracked the spread of SARS-CoV-2 in participants’ homes from May 2020 to February 2021.
People with eczema and asthma did not show additional vulnerability to the virus, but they also did not appear to be more protected.
People with food allergies, on the other hand, had a 50% lower risk of SARS-CoV-2 infection.
Not all forms of asthma are atopic (i.e. highly allergic), and previous studies have shown that only people with atopic asthma have lower levels of the ACE2 receptor in the airways, to which CoV-2 binds.
This suggests the virus doesn’t have as many ways to invade cells in the lungs of people with respiratory allergies.
A similar phenomenon could occur in people with food allergies, although the authors only looked at SARS-CoV-2 infection, not the severity of infection.
“It’s unclear if this is also the case in people with food allergies, but it’s tempting to speculate that type 2 inflammation, a hallmark of food allergy, may lower ACE2 levels. in the respiratory tract and therefore the risk of infection,” the researchers write.
“In support of this possibility, we found significantly higher levels of general atopy in people who reported a food allergy, compared to people without a food allergy, and even people with asthma. »
Interestingly, while some studies suggest that allergic asthma protects against severe cases of COVID-19, the current study showed that this condition does not protect against initial contraction of the virus.
Also, when a participant with asthma or food allergies contracted the novel coronavirus, they were no more likely to be asymptomatic.
More research is needed to unravel the mechanisms behind these new findings, but the authors hope their work can offer new avenues for COVID-19 prevention.