Researchers have found that drugs to lower the blood pressure of the type 'ACE inhibitors or angiotensin II receptor blockers' reduce the mortality rate of influenza and pneumonia.

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For the study, published in the Journal of the American Heart Association, the research team compared mortality rates among 5,00,000 Danish patients who were admitted to hospitals in Denmark with influenza and pneumonia during the period 2005 to 2018. "A little over 1,00,000 of the admitted patients took ACE inhibitors or angiotensin II receptor blockers, and the study shows that fewer of them were put on a ventilator and that they had lower mortality rates," said study author Christian Fynbo Christiansen from the Aarhus University Hospital in Denmark.

The study arrives mid in a discussion of treatment which peaked while the corona pandemic was at its height. Some medical doctors and researchers pointed out that ACE inhibitors may actually have the completely opposite effect - that is increasing the risk of dying from COVID-19 as the virus enters the lungs through the same ACE receptors as the ACE inhibitors. The hypothesis was that when the ACE inhibitor reduces the level of ACE, the body compensates for this by activating a much greater number of ACE receptors on the surface of the cells, which the SARS-CoV-2 virus then utilises as some kind of access key. According to the researchers, the greater the number of access keys available on the surface of the cells, the more easily the virus gains access to the cells.

The theory about increased mortality has been nurtured by the fact that a strikingly large proportion of the patients who were seriously ill due to COVID-19 had elevated blood pressure, which is extensively treated with ACE inhibitors. "We haven't examined whether what applies to patients with influenza and pneumonia can be transferred directly to patients with COVID-19, but there is some evidence to suggest that ACE inhibitors have a protective effect against lung damage which we don't see in patients who take other types of medicine to lower blood pressure," the authors wrote. The first studies find no correlation between ACE inhibitors/angiotensin II receptor blockers and COVID-19. However, further studies are needed using the good Danish registers," says Christian Fynbo Christiansen.