Getting the COVID-19 vaccine is an exciting moment that deserves to be celebrated. Before you reach for the champagne, it’s important to understand how alcohol might affect your response to the vaccine.

Drinking alcohol can affect your immune system and overall health. Your risk of experiencing the negative effects of alcohol increases the more you drink.

How Much Is Too Much?

Too much alcohol includes binge drinking and heavy drinking.

Studies show that women are more susceptible to the negative health effects of alcohol. This is why the recommended alcohol limits are lower for women than men.

The U.S. Centers for Disease Control and Prevention (CDC) recommends limiting alcohol to two drinks or fewer per day for men and one drink or fewer per day for women. This amount is considered moderate drinking.

Binge drinking is the most common form of excessive drinking. For women, four drinks or more on a single occasion is considered binge drinking. For men, five or more drinks on a single occasion is considered binge drinking.

The CDC defines heavy drinking as eight or more drinks per week for women and 15 or more drinks per week for men.

What counts as one drink differs depending on the type of alcohol:

• Beer — 12 ounces (360 milliliters)
• Malt liquor — 8 ounces (240 milliliters)
• Wine — 5 ounces (150 milliliters)
• Distilled spirits — 1.5 ounces (45 milliliters)

Alcohol Can Decrease Your Ability To Fight Infection

Alcohol use has both short-term and long-term effects on your immune response.

Studies show that the body’s ability to recognize foreign invaders, like bacteria and viruses, is decreased immediately after drinking. Over time, alcohol intake can harm your ability to fight infection by damaging cells and organs involved with your immune system.

Alcohol Increases Inflammation

Long-term alcohol use leads to increased inflammation all over the body. Inflammation is caused by the immune system.

Inflammation can be caused directly when alcohol comes into contact with the cells of your body, such as in your mouth, stomach, and intestines. When the cells become damaged, they release inflammatory signals.

Widespread organ damage can occur after the liver breaks down alcohol. Once alcohol is broken down, it makes reactive oxygen species that circulate in the body and cause inflammation and organ damage.

Alcohol Damages the Gastrointestinal System

The gastrointestinal (GI) tract is the main part of your digestive system. It’s a series of hollow tubes connected from your mouth to your anus that turns food into nutrients and energy. The nutrients are absorbed from your GI tract into your bloodstream.

The GI tract is the first point of contact for alcohol. Alcohol can directly damage the cells lining your GI tract, allowing pathogens like bacteria and viruses to enter the bloodstream.

Alcohol also decreases the number and variety of microbes in your gut. These microbes help you with digestion and are a vital part of the immune system. When alcohol alters your gut microbes, it can harm your immune system.

Alcohol Puts You at Risk for Other Chronic Health Conditions

Chronic heavy drinking puts you at risk for many health conditions. These health conditions can also decrease your ability to fight infection and put you at risk for more serious infections and include:

• Pneumonia
• Acute respiratory distress syndrome
• Heart disease
• Alcoholic liver disease
• Pancreatitis
• Certain types of cancer
• Seizures

According to the World Health Organization (WHO), chronic alcohol use is a risk factor for a severe case of COVID-19.

How Does Alcohol Affect Vaccine Response?

You aren’t considered fully vaccinated until two weeks after your second COVID-19 vaccine. This is because it takes your body a few weeks to learn how to fight the virus.

During this two-week period, the vaccine teaches your body how to recognize and then destroy the coronavirus that causes COVID-19.

Vaccines use harmless parts of the virus as antigens, which are substances that activate the immune system. The immune system uses the antigens to make proteins, called antibodies, that will recognize the antigen. When you run into a virus with that specific antigen again, your immune system already knows how to make the right antibodies, which mark the virus for destruction.

For a vaccine to be effective, your immune system must be working well. People who have a weakened immune system may not have a strong response to the COVID-19 vaccine.

Can Binge Drinking Affect Vaccine Response?

There isn’t any research to show how binge drinking can affect vaccine response. However, a study on young, healthy human volunteers found that five hours after binge drinking, their immune system was suppressed.

We don’t know yet whether this means that binge drinking after getting the vaccine will decrease your response to the vaccine. If binge drinking decreases your response to a vaccine, we also don’t know if that means you will be less protected from getting the disease in the future.

Can Long-Term Drinking Affect Vaccine Response?

Scientists already know that long-term alcohol use weakens your immune system, but there is not much information about what that means for vaccine response.

Researchers have found that daily alcohol consumption may prevent the body from making antibodies after the COVID-19 vaccination. A study in Japanese health care workers found that COVID-19 antibody levels were 15 percent lower in daily drinkers when compared to people who do not drink, after getting the third dose of the Pfizer vaccine.

This is early evidence, and it’s unclear whether the decrease in antibodies means someone is more likely to get COVID-19.

Hangover Symptoms May Be Similar to Vaccine Side Effects

Public health experts at the South African Vaccination and Immunisation Centre warn that hangover symptoms are easy to confuse with the side effects of the coronavirus vaccine.

Many of the common symptoms of a hangover overlap with vaccine side effects, such as:

• Tiredness
• Headache
• Muscle aches
• Nausea

Adding hangover symptoms to vaccine side effects may make you feel worse. If you can’t tell if how you’re feeling is caused by hangover symptoms or vaccine side effects, you will not be able to accurately report vaccine side effects. This issue will negatively affect side effect reporting and monitoring.

The Bottom Line

The COVID-19 pandemic is not over yet. It is important that you get the COVID vaccine and any recommended vaccine boosters to make sure you are protected against COVID-19 variants and severe disease. Talk to your health care provider about which vaccine may be right for you and if you should get a booster.

As with most things in life, alcohol is best in moderation. Daily drinking, binge drinking, and heavy drinking lower your ability to fight infections like COVID-19. Alcohol also increases your risk of many harmful health conditions.

The COVID-19 vaccine is new, so there is not enough evidence to say how alcohol may affect your body’s response to the vaccine. Consider avoiding alcohol or decreasing the amount you drink for a few days after receiving your COVID-19 vaccine.

Talk With Others Who Understand

On myCOVIDteam, the online social network for people with COVID-19 and their loved ones, more than 7,000 members come together to ask questions, give advice, and share their stories with others who understand life with COVID-19.

Did you have side effects from the COVID-19 vaccine? Share your experience in the comments below, or start a conversation by posting on your Activities page.