Harvard researchers recently published their findings regarding allergic disorders and susceptibility to Covid-19. The study was conducted on 220,000 people between January and May of this year.
Previous to this study it has been known that people at greater risk for and from this virus include those: over 65, with pre-existing lung disease, with chronic kidney disease, with diabetes, with hypertension, with heart disease, obesity, with cancer, smokers, with immune compromising illnesses, with organ transplants and with HIV. Now it appears that underlying allergy also confers greater risk.
It has been known for many years that underlying allergic respiratory problems predispose to other types of respiratory infections from colds, to ear and sinus infections to bronchitis and pneumonia. It has also been known for years that treating the underlying allergy reduces this risk. Now, it seems that allergy predisposes to both catching Covid-19 and having a more serious outcome. People with either allergic rhinitis or asthma have this increased risk. The scientists feel the increased risk from allergy is probably multifactorial, but one aspect recently discovered is an increase in one of the cellular attachment proteins: TMPRSS2.
In order to enter the human body Covid-19 has to use certain available “doors” called cell receptors. The more “doors” available, the more readily the virus can enter. Allergic inflammation increases the number of TMPRSS2 doors.
The researchers went on to speculate that having good control of the allergic condition (and thereby reducing the inflammation) should help reduce this increased risk.