Alcohol, Vaccines, And COVID-19: What We Know So Far

The global response to COVID-19 has shown the best and worst of our ability to share information. Rumor and suspicion have been present in equal measure to common sense and scientific data. Among fears that alcohol will impair your immune response to the COVID vaccine there are murmurings that tannins in wine will help fight the virus in humans.

Here, we attempt to draw a distinct line between fake news and the facts for those of us who like to drink during the pandemic. 

Prompted by various and contradicting claims concerning alcohol and COVID-19; from suggestions that drinks may have a beneficial role in combating the virus, to others who claim that booze will have a negative effect – Dr. Nicolai Worm, Chair of the Wine Information Council, led a seminar on recent and newsworthy stories on the subject.  

Called Wine and COVID-19: fake news or facts?, the online event discussed the scientific studies that could be used to support or refute claims surrounding three topics in particular: alcohol and the immune function in general; drinking and fighting COVID-19, and the impact of wine on vaccinations.

The key findings from this insightful event are shared below.

Whilst the World Health Organization has told people “to avoid alcohol altogether” during the pandemic, “so that you do not undermine your own immune system” credible scientific studies suggest that moderate wine drinking may actually boost immune responses to vaccinations. Furthermore, there is no correlation recorded between drinking and an increased likelihood of hospitalisation following a COVID infection.

Dr Nicolai Worm – who is a nutrition consultant, lecturer and professor of nutrition at the German University of Prevention and Health Care Management – said, when it comes to drawing conclusions from studies involving alcohol, people should check two key things.

The first consideration was whether it was an ‘in vivo’ study, since it is impossible to draw credible conclusions on human responses from ‘in vitro’ lab-based research.

The second consideration was whether the research differentiates between moderate or heavy drinkers.

While moderate drinkers represent the majority of consumers, it is the heavy use of alcohol that features in studies – and, because alcohol abuse is connected to a range of health problems, these subsequently become associated with all levels and patterns of drinking.

Below is a three-part summary of the findings from Wine and COVID-19: fake news or facts? Seminar,  web-based seminar led by Dr. Nicolai Worm on March 2, 2021.

1. ALCOHOLIC BEVERAGES AND THE IMMUNE FUNCTION

• The consumption of alcoholic beverages can influence the immune system through multiple mechanisms, altering both innate and adaptive (*) immune function.
• The vast majority of research on alcohol and immune function and risk of infectious diseases is conducted on chronic heavy drinkers or people with alcohol use disorders.
• Heavy drinkers are more susceptible to pneumonia and to bacterial and viral respiratory infections.
• Binge drinking may also suppress immune response, but this response appears to be temporary.
• In comparison, very few studies have been conducted among light and moderate drinkers.
• Moderate drinking has been associated with either no risk or decreased risk of respiratory infections in some studies.
• To date there is no/insufficient evidence demonstrating an increased risk of infection associated with light or moderate drinking.

(*) The innate immune response is the immediate responder part of the immune system and is non-specific to an invading pathogen, whereas the adaptive system is activated in response to a specific pathogen or antigen; it can recognise and immediately defend against a previously encountered pathogen, but it can also be activated by the innate immune response.

 2. DOES WINE DRINKING (ALCOHOL / POLYPHENOLS) HELP FIGHT COVID-19?

• In in-vitro studies, it was shown that polyphenols (flavanols, proanthocyanidins) in grapes and wine prevented the SARS-CoV-2 virus from attaching itself to human cells. This was only one study related to SARS-CoV-2 virus and it was an in-vitro study.
• The results cannot be extrapolated to humans, and needs to be repeated in animal and human studies.
• It was shown in animal studies that the spreading of the flu virus, not the SARS-CoV-2 virus, could be prevented by blocking its enzyme.
• Some wine phenolic compounds can prevent the multiplication of the Mers-virus (another corona virus but not SARS-CoV-2 virus), by preventing attachment or invasion in the host cell.
• Some (wine) polyphenols destroy the synthesis or composition of the genetic material or the shell of viruses.
• Flavonoids in wine could stop the advancement of the flu and limit its symptoms. A possible mechanism may be that wine polyphenols influence the immune system through the gut microbiota. However, whether these mechanisms work against the COVID-19 virus in vivo in humans has not been studied/shown in appropriate studies.

3. DOES WINE CONSUMPTION MAKE COVID-19 VACCINATION INEFFECTIVE

• There is very limited research on light or moderate consumption of wine/alcoholic beverages and immune response to vaccines.
• A small number of animal and human studies have examined the effect of alcohol consumption on the immune response following vaccination – however, no studies have been published so far on alcoholic beverages and response to a COVID-19 vaccine.
• Some indication exists that moderate consumption of alcoholic beverages may assist the immune response to the vaccine, potentially through an anti-inflammatory effect of the wine polyphenols, however, there is an insufficient amount of research to form a conclusion.