Chronic Alcohol Use May Increase Risk for SARS-CoV2 Infection, Study Suggests

A newly published animal study found that chronic alcohol consumption may create conditions in the body that can facilitate infection by SARS-CoV2, the virus that causes COVID-19 disease. The study, published in Alcohol: Clinical and Experimental Research, found that chronic alcohol use increased the levels of an enzyme that helps the virus enter the cells and, therefore, may increase the risk for COVID-19.

The researchers exposed rats to ethanol vapor using scientific models to mimic chronic alcohol use and alcohol dependence. The authors then examined the organs typically affected in COVID cases—the lungs, liver, heart, brain, kidney, and small intestine–to understand the effects of alcohol exposure on enzymes involved in SARS-CoV2 infection. They analyzed three enzymes, ACE2, TMPRSS2, which help facilitate entry by the virus into the cell, and Mas, which exerts a protective, anti-proliferative and anti-inflammatory effect after the virus enters the cell.

The study found that, following chronic alcohol exposure, ACE2 levels in the lungs increased, which, the researchers suggest, could lead to an increased probability of the SARS-CoV2 virus entering and infecting the cells of the lungs.  Additionally, after a period of abstinence from alcohol exposure, an increased anti-inflammatory response was observed, suggesting a protective effect from stopping drinking.

The researchers noted that TMPRSS2 levels increased overall, without organ-specific effects, in rats exposed to alcohol, which may mean that blood alcohol concentration may help accelerate virus infiltration into the cell. Brain tissue appeared to be less vulnerable to virus-promoting effects of alcohol, except in the olfactory bulb, where levels of the protective enzyme Mas decreased, which could result in a lower anti-inflammatory response in the olfactory bulb and thus lead to anosmia, or loss of smell.

This study’s findings of increased ACE2 after chronic alcohol use may help explain epidemiological data, which has shown people with alcohol use disorder to have higher rates of COVID infection and worse disease prognosis. Previous studies have found that chronic alcohol use disrupts the body’s immune system, and the amount of alcohol consumed per week has been associated with acute respiratory distress syndrome after SARS-CoV2 infection.

This study demonstrates the impact of chronic alcohol exposure on enzymes that play a role in the infection and proliferation processes of SARS-CoV2 at the molecular level. More research, such as analysis of the genes of SARS-CoV2 infected rodents after chronic alcohol exposure, is needed to understand COVID-19 disease risk and progression.  

Chronic alcohol intake regulates expression of SARS-CoV2 infection-relevant genes in an organ-specific manner. M. Friske, F. Giannone, M. Senger, R. Seitz, A. Hansson, R. Spanagel (p. x- x)

ACER-22-5392.R2