TORONTO -- As the first COVID-19 vaccines are rolled out across Canada, questions have been raised as to whether drinking alcohol will affect people’s immune response to the shot.

Experts around the world have offered differing opinions on the matter. Some say you should avoid drinking alcohol before receiving the vaccine, and others say alcohol consumption is not an issue and will not affect the efficacy of the COVID-19 vaccines.

There is no specific data surrounding COVID-19 vaccines, moderate alcohol use, and alcoholism, but there is good reason for that, says Toronto physician and clinical researcher Dr. Iris Gorfinkel.

“In vaccine trials and in research trials in general, when someone has pretty extreme [alcohol] use, they'll be excluded from the trial for several reasons,” Gorfinkel explained in a telephone interview with Saturday.

“The problem is this. If I include a person who suffers severe alcoholism in the trial, I do so at the risk of not understanding, if this person should have liver failure or a severe problem,…I will not know if [the results] are related to that serious pre-existing problem or is it related to the vaccine that I just gave them.”

Gorfinkel stressed that she would suggest that everybody, “no matter how much alcohol they drink,” should get vaccinated.

“Alcohol should not be a barrier to getting the vaccine, period,” she said.

Alcoholism is linked to several comorbidities, that “go beyond liver cirrhosis” to issues like hypertension, diabetes and cardiovascular disease, putting alcoholics at higher risk, Gorfinkel explained.

“COVID- 19, has been associated with comorbidities and comorbidities hold hands with alcohol,” she said.

“Those patients who are at increased risk of COVID-19… the enlightened question really is where is your greater risk? Is it through vaccination or is it your natural disease?” she said.

“And the answer is, resoundingly hands down - the lesser damage is done by vaccination.”

It is a sentiment echoed by infectious disease expert Dr. Abdu Sharkawy, who called concerns about alcohol consumption and COVID-19 vaccines “theoretical.”

“Obviously excessive consumption of alcohol has a wide range of detrimental health effects, including possible immune dysfunction,” Sharkawy said in an email to Saturday.

“Theoretically this could affect reaction to a vaccine in an adverse manner or lead to lesser likelihood of immune response. However, there is no strong evidence to back this up,” he said.

Sharkawy expressed “concern” that people could be discouraged from taking the vaccine if it is not clear that questions surrounding alcohol and COVID-19 vaccines they may see online are “a hypothetical issue more than anything.”

In an emailed statement to, Health Canada said it “has not issued a warning about avoiding alcohol intake before or after immunization against COVID-19. None of the current vaccines have warnings related to alcohol intake, as there is no evidence of interference from alcohol intake on vaccination efficacy or safety that would require such a warning.”

However, Health Canada did echo Gorfinkel and Sharkawy’s general concerns over alcoholism, saying “regular heavy drinking could interfere with your body’s ability to build immunity. Anyone concerned about this issue should speak with their healthcare provider.”

For those who are casual alcohol consumers, whether or not you drink just before receiving a COVID-19 vaccine, Gorfinkel said there are “zero” issues.

“No issues whatsoever. Once it becomes available to everybody, whether or not a person has a glass of wine or anything, that's not going to profoundly impact their immune response to the vaccination,” she said.

Concerns over alcohol exacerbating allergic responses when receiving a COVID-19 vaccine through vasodilation, or the widening of blood vessels, were similarly dismissed by both Gorfinkel and Sharkawy.

“In the millions of doses of the Pfizer and Moderna vaccine administered thus far, allergic reactions have been both extremely rare, and with no association identified with alcohol intake,” Sharkawy wrote in his email. 

“As soon as there is any vasodilation that will increase localized histamines,” Gorfinkel said, stressing that “association is not causation.”

“There’s a theoretical link. There’s the theory and there’s the practical…and guess what? It is not a predictor of an allergic response,” she said.

Gorfinkel said that anyone concerned about their alcohol intake in relation to getting a COVID-19 vaccine should talk to their doctor.