From the beginning of the Covid19 pandemic, we immediately realized that some subjects were more severely affected by the disease than others. A parameter that correlates with the severity of the disease is age, in fact we know that the lethality rate doubles every 5 years and therefore the older subjects are those most at risk of serious disease. We also know that obesity is an important co-factor that can worsen the outcome of Covid19 as well as type 2 diabetes and hypertension. These are just some of the prognostic factors that indicate the risk of a particularly violent disease.
Are there any factors that correlate with a less severe disease?
A protective factor, not yet explained today, is being a woman; in fact it seems that women are generally less exposed to the risks of Covid19. Other factors concern the general state of health, a complete and balanced nutrition and recently food allergies have been added to the protective factors.
In fact, from a recent study on a population of 4000 people it emerged that subjects with food allergies have a 50% reduced risk of becoming infected with Sars-CoV2 compared to non-allergic subjects.
It was also observed that asthmatics (a particularly violent condition of inflammation of the upper airways following exposure to an allergen) had a sort of protection against severe forms of Covid19.
The second observation is the most interesting as it would be expected that asthmatics and therefore with a respiratory condition are more at risk when they contract a respiratory virus such as Sars-CoV2.
There is no explanation yet
For both observations at the moment there is no single and robust explanation but there are some hypotheses that try to explain them. Food allergies and allergic asthma are conditions of hyper-activation of the immune system which reacts exaggeratedly against food (food allergies) or against pollen, dust, animal hair, etc.
So a hyper activated immune system is an immune system ready for action in the event of a true infection such as Sars-CoV2. Obviously this mechanism is not physiological and our body does not benefit from a hyper-activation of the immune system. Overactivation of the immune system can lead to anaphylactic shock where the immune response is so violent that it can lead to death.
A second explanation
A second possible explanation is that allergic and asthmatic subjects have less ACE2 in the upper respiratory tract and this would prevent Sars-CoV2 from entering our body. ACE2 is the ‘door’ that Sars-CoV2 uses to enter our cells and initiate infection, it is assumed that children, less affected by the disease, express less ACE2 than the elderly.
Finally, it is hypothesized that allergic and asthmatic subjects are more protected from Covid19 due to their behaviors: in addition to the use of cortisone-based inhalers, asthmatic subjects potentially use more precautions than a ‘healthy’ subject. The presence of allergies and asthma could induce less risky behaviors and therefore less exposure to contagion.
Don’t change the way you behave
The one described is a very strong correlation that indicates that allergic subjects are more protected from infection and that asthmatic subjects are less likely to develop a serious disease, obviously this information must in no way change the behavior of people (allergic or not) since we don’t know how individuals will respond to the virus.
TAKE HOME MESSAGES:
- there are several risk factors for Covid19: age, obesity, diabetes, hypertension
- there are protective factors, food allergies among them
- allergic and asthmatic subjects are less prone to infection and more severe forms of Covid19
- there are at least three hypotheses that explain this correlation but they must be confirmed
REF.
https://www.jacionline.org/article/S0091-6749(22)00752-7/fulltext
https://link.springer.com/content/pdf/10.1007/s12016-022-08921-5.pdf
https://erj.ersjournals.com/content/early/2020/10/29/13993003.03045-2020
Aureliano Stingi, doctor in molecular biology works in the field of precision oncology. He collaborates with the World Health Organization in the battle against Covid19-themed fake news
Instagram: Aureliano _Stingi