People with food allergies may have a reduced chance of getting infected with SARS-CoV-2, the virus that causes COVID-19, new research suggests.
The study, published in the Journal of Allergy and Clinical Immunology and funded by the National Institutes of Health, found that having a self-reported and physician-diagnosed food allergy—a condition that affects an estimated 32 million people in the U.S.—cut the risk of infection by SARS-CoV-2 in half.
"In general, when you study how complex diseases and infections work, there's always some portions of the population that are more or less susceptible," lead study author Max Seibold, PhD, a researcher at National Jewish Health, told Health.
The study also determined that people with asthma—who were previously thought to have an increased risk of COVID-19—did not have a greater likelihood of catching the virus.
Although more research is needed to explain these findings, Dr. Seibold said that they may provide some comfort to certain populations that were previously unsure of their risk levels. "There's a lot of fear in that community on whether they might be a group that's susceptible to poor outcomes," said Dr. Seibold.
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Food Allergies Can Cut COVID-19 Risk in Half
For the new study, researchers set out to determine whether children and people with allergic diseases and asthma were at a greater risk of being infected with SARS-CoV-2. To do that, they monitored more than 4,000 people across nearly 1,400 households for cases of COVID-19 between May 2020 and February 2021—before the rollout of COVID-19 vaccines for the general public, and before many variants of concern were identified.
All households included at least one person under the age of 21, and about half of the participants had a self-reported food allergy, asthma, eczema, or allergic rhinitis. People in each household took weekly symptom surveys, and were given nasal-swab tests every other week.
Research showed that people with self-reported, physician-diagnosed food allergies had a 50% lower risk of SARS-CoV-2 infection. Meanwhile, asthma, eczema, and allergic rhinitis were not associated with an increased or decreased risk of COVID-19.
It's unclear why food allergies were associated with a reduced risk of COVID-19. Researchers examined the idea that maybe people and households with food allergies were less likely to dine out at restaurants, ultimately lessening their community exposure. But that theory became less plausible once researchers discovered food-allergic households had only slightly lower levels of exposure than other households.
Instead, Dr. Seibold said it may have something to do with ACE2 receptors—proteins found on the surface of some cells that provide an entryway for the SARS-CoV-2 virus. He noted a certain type of inflammation, type 2 inflammation, is common in people with allergic diseases, and reduces airway ACE2 levels, ultimately reducing the risk of infection. "This decreases the chance of the virus getting in, which is something that we're actively investigating right now," said Dr. Seibold.
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People With Food Allergies Still Need to Protect Against COVID-19
It's important to note that this new research does not mean people with food allergies have a free pass from practicing COVID-19 precautions like getting vaccinated or masking in certain situations. Food allergies cannot completely protect people from contracting the virus, Clifford Bassett, MD, an allergist-immunologist at NYU Langone Health, who was not involved in the study, told Health.
Because this research also took place between 2020 and 2021—before widespread vaccination or more infectious variants of the coronavirus emerged—it's unknown how much of this research is still valid today, particularly as more and more Omicron subvariants arise and begin to spread.
"I believe this study does not indicate that people with food allergies are protected from COVID," said Dr. Bassett. "In fact, those with food allergies, just like most of us, should get vaccinated and also wear masks—when it is appropriate to do so—to limit the risk of getting COVID."
Dr. Seibold also warned against over-interpreting the results of the study. "I wouldn't recommend anyone change their choices on how to protect themselves, based on having [food allergies]," he said.
For maximum protection against COVID-19, the Centers for Disease Control and Prevention (CDC) recommends everyone ages 6 months and older receive a primary series of a COVID-19 vaccine, with a preference for mRNA options. Anyone over 5 years old is recommended to stay up to date on COVID-19 vaccination with boosters, if eligible.
The study, published in the Journal of Allergy and Clinical Immunology and funded by the National Institutes of Health, found that having a self-reported and physician-diagnosed food allergy—a condition that affects an estimated 32 million people in the U.S.—cut the risk of infection by SARS-CoV-2 in half.
"In general, when you study how complex diseases and infections work, there's always some portions of the population that are more or less susceptible," lead study author Max Seibold, PhD, a researcher at National Jewish Health, told Health.
The study also determined that people with asthma—who were previously thought to have an increased risk of COVID-19—did not have a greater likelihood of catching the virus.
Although more research is needed to explain these findings, Dr. Seibold said that they may provide some comfort to certain populations that were previously unsure of their risk levels. "There's a lot of fear in that community on whether they might be a group that's susceptible to poor outcomes," said Dr. Seibold.
CDC Recommends COVID Vaccines for Kids Under 5—Here's When Shots Could Go in Little Arms
Food Allergies Can Cut COVID-19 Risk in Half
For the new study, researchers set out to determine whether children and people with allergic diseases and asthma were at a greater risk of being infected with SARS-CoV-2. To do that, they monitored more than 4,000 people across nearly 1,400 households for cases of COVID-19 between May 2020 and February 2021—before the rollout of COVID-19 vaccines for the general public, and before many variants of concern were identified.
All households included at least one person under the age of 21, and about half of the participants had a self-reported food allergy, asthma, eczema, or allergic rhinitis. People in each household took weekly symptom surveys, and were given nasal-swab tests every other week.
Research showed that people with self-reported, physician-diagnosed food allergies had a 50% lower risk of SARS-CoV-2 infection. Meanwhile, asthma, eczema, and allergic rhinitis were not associated with an increased or decreased risk of COVID-19.
It's unclear why food allergies were associated with a reduced risk of COVID-19. Researchers examined the idea that maybe people and households with food allergies were less likely to dine out at restaurants, ultimately lessening their community exposure. But that theory became less plausible once researchers discovered food-allergic households had only slightly lower levels of exposure than other households.
Instead, Dr. Seibold said it may have something to do with ACE2 receptors—proteins found on the surface of some cells that provide an entryway for the SARS-CoV-2 virus. He noted a certain type of inflammation, type 2 inflammation, is common in people with allergic diseases, and reduces airway ACE2 levels, ultimately reducing the risk of infection. "This decreases the chance of the virus getting in, which is something that we're actively investigating right now," said Dr. Seibold.
What Is 'Paxlovid Rebound'? CDC Warns of COVID-19 Recurrence After Antiviral Treatment
People With Food Allergies Still Need to Protect Against COVID-19
It's important to note that this new research does not mean people with food allergies have a free pass from practicing COVID-19 precautions like getting vaccinated or masking in certain situations. Food allergies cannot completely protect people from contracting the virus, Clifford Bassett, MD, an allergist-immunologist at NYU Langone Health, who was not involved in the study, told Health.
Because this research also took place between 2020 and 2021—before widespread vaccination or more infectious variants of the coronavirus emerged—it's unknown how much of this research is still valid today, particularly as more and more Omicron subvariants arise and begin to spread.
"I believe this study does not indicate that people with food allergies are protected from COVID," said Dr. Bassett. "In fact, those with food allergies, just like most of us, should get vaccinated and also wear masks—when it is appropriate to do so—to limit the risk of getting COVID."
Dr. Seibold also warned against over-interpreting the results of the study. "I wouldn't recommend anyone change their choices on how to protect themselves, based on having [food allergies]," he said.
For maximum protection against COVID-19, the Centers for Disease Control and Prevention (CDC) recommends everyone ages 6 months and older receive a primary series of a COVID-19 vaccine, with a preference for mRNA options. Anyone over 5 years old is recommended to stay up to date on COVID-19 vaccination with boosters, if eligible.
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Trung Nghĩa, Hòa Ninh, Hòa Vang, Tp Đà Nẵng, Việt Nam 
