In the course of the Covid-19 pandemic, we have discovered who may be at greatest risk of contracting the virus and developing the most severe cases of the disease.
Advanced age, obesity and various comorbidities such as diabetes and hypertension are some of these risk factors. High body mass index (BMI) also appears to be associated with an increased chance of contracting the virus in the first place.
But what about the factors that can make someone less likely to get covid? Interestingly, research shows that having allergies can reduce your risk.
Allergies are very common. At least 400 million people worldwide are affected by pollen allergies, known in English as hay fever. About 300 million people suffer from allergic asthma (induced by inhaling allergens), while food allergies affect about 250 million.
Many people are also allergic to certain medications. Allergic reactions can range from mild (perhaps some redness and swelling of the skin) to severe (anaphylactic shock, which can cause death)
Atopic diseases is a name given to a group of conditions triggered by allergens and include eczema and dermatitis. Research has shown that people with atopic diseases are 25% less likely to contract covid. For people with atopic disease and asthma, the risk is 38% lower compared to people without these conditions.
Another study showed that people with food allergies were 50% less likely to be infected and have covid.
Initially, we thought that people with allergies might be less likely to get covid because they might be more isolated from others. This may be true for asthma because people with this condition were advised to protect themselves early in the pandemic.
But that logic doesn’t hold for most atopic diseases, like eczema. And while we might expect that people with food allergies, say, ate less outside, research during the pandemic showed that families with food allergies had only slightly lower exposure levels in the community compared to other families.
In order to infect the body, Sars-CoV-2 (the virus that causes covid) binds to a specific protein called the ACE2 receptor. This protein provides the entry point for the virus to infect a wide range of human cells.
Having greater amounts of ACE2 receptors is associated with a greater susceptibility to covid infection. People who smoke, have diabetes or high blood pressure (all associated with an increased likelihood of severe covid) have more ACE2 receptors.
Meanwhile, type 2 inflammation — a normal immune reaction that can occur in response to infections or parasites, but also occurs prominently in allergic conditions — has been shown to reduce the manifestation of ACE2 in the airways.
This lowers susceptibility to infection and is considered to be the main reason people with allergies appear to have a lower risk of catching Covid.
There are also a number of other factors that can contribute to reducing the risk of Covid infection among people with allergies.
For example, those who have asthma tend to produce more mucus than others, which is understood as something that makes it difficult for Sars-CoV-2 to enter the airways.
other good news
So we see a reduced risk of getting covid in people with allergies and asthma. But how do these conditions affect the severity of a covid infection?
At the beginning of the pandemic, it was assumed that people with asthma could be at greater risk of developing more severe cases of the disease, because viral infections often exacerbate asthma. But it is now well established that mild or well-controlled asthma does not increase the risk of severe Covid cases. Nor does the evidence indicate that more severe asthma increases risk.
Likewise, atopic disease is not considered a risk factor for severe covid.
If you suffer from other illnesses in combination with asthma or allergies, it is important to be aware that this can increase the severity of covid.
Prevention remains essential. The best ways to prevent covid infection include vaccination, wearing appropriate masks and physical distancing.
In the meantime, if you have allergies, having an allergy management plan is essential. Make sure your treatment plan is up to date and that you have medications on hand in case you need them.
*Samuel J. White is Senior Lecturer in Genetic Immunology at Nottingham Trent University (UK). Philippe B. Wilson is Professor of One Health also at Nottingham Trent University.
Have you watched our new videos on YouTube? Subscribe to our channel!
#allergies #reduce #risk #contracting #covid #BBC #News #Brazil