But how can you make sure you get the most out of your dose or two? Does your diet matter? How about lifestyle choices? If you have these questions, you’re not alone. There are even supplements on the market that claim they can boost your immune system, increasing the effectiveness of your vaccine. Whether that’s true — and whether you can really optimize your body’s vaccine response — is up for debate. Here’s what you need to know, so you can rest easy after signing up to get inoculated. RELATED: 10 Misconceptions About the Coronavirus

How the COVID-19 Vaccines Work to Bolster Your Body’s Immune Response

Here’s a little vaccine 101. Currently, there are three COVID-19 vaccines approved by the Food and Drug Administration (FDA) and available in the United States. Among them, there are two types of vaccines, mRNA (Pfizer-BioNTech and Moderna) and viral vector (Johnson & Johnson’s Janssen). “Vaccines are a medical marvel. They allow our immune systems to learn how to recognize infectious invaders like bacteria and viruses without making you sick in the process,” says David Stukus, MD, an immunologist with Nationwide Children’s in Columbus, Ohio, and a member of the American Academy of Allergy, Asthma & Immunology COVID-19 Response Task Force.

Pfizer’s and Moderna’s COVID-19 Vaccines

The way that the mRNA vaccines do that is by giving your cells instructions to make a harmless piece of the spike protein of the virus. “Our adaptive immune system gets very good at recognizing foreign invaders, and it helps build antibodies if we encounter these infections in real life,” says Dr. Stukus. Your immune system then rapidly recognizes the virus and can fight it off. The Pfizer-BioNTech COVID-19 vaccine is 95 percent effective in preventing symptomatic infection and 100 percent effective in preventing severe disease, according to the Centers for Disease Control and Prevention (CDC). Moderna’s vaccine is 94 percent effective and 89 percent effective in preventing hospitalization, says the CDC.

Johnson & Johnson’s COVID-19 Vaccine

The Janssen vaccine from Johnson & Johnson uses a more traditional method by introducing a modified version of an adenovirus (this is inactivated, so it can’t make you sick) to instruct the cell to make the spike protein. “Once in there, our immune system recognizes the spike protein and we form the same immune response,” says Stukus. According to a March 2021 article published in The Journal of the American Medical Association, the Janssen vaccine was 66 percent effective in preventing moderate to severe infection, and 100 percent effective at preventing hospitalization and death related to COVID-19. Despite the vaccines’ different efficacy rates, research is still emerging on how they perform when faced with infection from newer strains of COVID-19. Plus, authorities have emphasized the importance of getting the first vaccine made available to you in order to promote herd immunity, which occurs when a population is protected from infection via past infection or vaccination, as the World Health Organization notes. RELATED: 8 Biggest COVID-19 Vaccine Myths

Can BMI Affect COVID-19 Vaccine Efficacy?

Speaking of ongoing research, questions remain about if your body mass index (BMI) influences your response to the vaccine. As Pfizer points out, efficacy was consistent across varying factors, including age, gender, BMI, obesity, and underlying comorbidities (having two or more medical conditions at the same time). That said, people who fit into the obese BMI category (a BMI above 30) may be eligible for vaccination at this time, depending on their state rules. This is because obesity is linked to more severe illness from COVID-19, notes the CDC. RELATED: Obesity May Increase the Risk for COVID-19 Complications

Can Lifestyle Factors Influence the Effectiveness of the Vaccines for COVID-19?

As mentioned, it’s important to understand what scientists have data on — and what they’re still investigating. “Regarding the COVID-19 vaccines, there is zero evidence that lifestyle factors influence vaccine response. This is all too new and where pseudoscience reigns supreme,” Stukus says. Watch out for products that are geared toward improving your vaccine response or boosting your immune system in general. In fact, Stukus says, “boost the immune system” is a marketing term, not one that immunologists use. “Overall, our immune systems are robust and very complex. The vast majority of people should have zero concerns that their immune systems will not respond well to these vaccines,” he adds. Exceptions include extreme sleep deprivation, malnourishment, alcoholism, or a severe chronic illness, all of which may impact your response, says Stukus. The one evidence-based way to “boost your immune system” against COVID-19 is through a vaccine, he explains.

How Factors Like Stress, Diet, and Sleep May Influence Immunity

There is a difference between things that could “boost” your immunity and factors that may decrease your immune system function and response. And that’s where you may be able to take actionable steps to support your body, suggests a January 2021 study published in Perspectives on Psychological Science that analyzed 30 years of data and 49 vaccine studies in humans. Key caveat: The researchers did not analyze the COVID-19 vaccines, though the findings may still be relevant. Previous research has shown that significant life stressors may leave you more susceptible to illness. In the new study, researchers wanted to look at if daily stressors have a similar impact and what the clinical relevance may be when it comes to vaccines. “We found that the people who were more stressed and anxious for a short period of time before the vaccine took longer to develop antibodies to a vaccine. And this applied to young, healthy students,” says Annelise Madison, a doctoral candidate in clinical psychology at The Ohio State University in Columbus and first author of the study along with Janice Kiecolt-Glaser, PhD. RELATED: Is Stress Making You Sicker? Signs You Should Never Ignore Study authors also found evidence that stressed students saw more side effects (like fatigue) to the vaccine; the duration of immunity following a vaccine may also be reduced, which would perhaps necessitate a more frequent booster vaccination, Madison points out. It may be neuroendocrine or inflammatory changes that occur with stress and mental health conditions like depression behind this effect. People who are stressed or depressed are also less likely to have overall healthy habits, including quality sleep, proper nutrition, and regular exercise, she says. First, it’s important to know that the past studies they analyzed did not include the COVID-19 vaccines. (They did, however, include vaccines for conditions such as hepatitis B, influenza, and pneumonia.) Research would need to be done on the COVID-19 vaccines specifically to understand how psychological and behavioral factors may influence the response, says Madison. These vaccines are highly efficacious, particularly when it comes to preventing severe illness, so researchers would need to explore how much these factors really matter.

Healthy Habits to Practice Before and After COVID-19 Vaccination (and Always)

It’s always beneficial to your body to practice good health habits — whether you have a vaccine appointment on the calendar or not. Here are the things you may want to pay attention to right now:

Don’t Smoke or Abuse Alcohol

Smoking and abusing alcohol are linked to weakened immunity, according to the CDC and past research, respectively. For alcohol, it’s best not to have more than two drinks per day if you’re a man, suggests the CDC. Meanwhile, women should drink only one alcoholic beverage per day. In general, the less alcohol you drink, the better off your health may be.

Eat a Healthy, Balanced Diet Rich in Whole Foods

As the Perspectives on Psychological Science paper notes, “Although a single nutrient or nutrient deficiency may have little impact on vaccine response, overall diet may be an important consideration.” That would mean moving away from the standard American diet of processed foods and added sugar and toward a more fresh, whole-foods-based approach. It’s best to focus on this pattern of eating for life rather than a set point in time. Chicago-based Dawn Jackson Blatner, RDN, recommends against taking specific supplements designed to enhance your immune system and instead focus on eating fruit and vegetables, whole grains, beans and lentils, and nuts and seeds. She also suggests decreasing refined sugars and flour in your diet to support all of your body’s systems, including immunity. While it’s not clear if eating this way before or after receiving the COVID-19 vaccine will have a significant effect, it does not hurt to make these healthy diet choices. Supplements, however, can be unnecessarily expensive and may give you a false sense of security. “Taking a pill will not make up for being stressed, sleep deprived, or not physically active,” she says. RELATED: 7 Foods That Fight Back: Immune System Boosters

Prioritize Sleep Quality and Length

Nab seven to nine hours of sleep per night, according to the National Sleep Foundation. Your immunity depends on it. Sleep-deprived individuals are more susceptible to becoming sick when exposed to other viruses, like the rhinovirus, which causes the common cold, says sleep researcher Rebecca Robbins, PhD, an instructor in medicine at Harvard Medical School in Cambridge, Massachusetts. Sufficient sleep also allows your body to mount an appropriate immune response when you come into contact with pathogens. As researchers write in a March 2021 editorial published in The Lancet Respiratory Medicine, some studies even suggest that a good night’s sleep on the nights before and after you receive some vaccines can boost their efficacy, though those studies did not include the new COVID-19 vaccines. Observational research she authored in February 2021 in the Journal of Medical Internet Research found that the pandemic increased sleep time for many individuals, something that could favorably affect your immune system. “We believe that coupling your vaccination appointment with good sleep the week before and after may help set you up for success,” says Robbins.

Keep Stress Levels Under Control

This might be done through, for example, exercise, getting more sleep, connection with loved ones, or your favorite stress-reduction strategies. Seeking help for existing mental health conditions, like depression or anxiety, is important, and the benefits extend far beyond the topic at hand. RELATED: Can Taking a Vitamin D Supplement Help Protect Against COVID-19?

More Studies on Diet, Lifestyle, and the COVID-19 Vaccine Are Needed

Overall, while psychological or behavioral factors may impact the amount of time it takes to develop an immune response to a vaccine — and remember, this still needs to be explored in terms of the COVID-19 vaccine — you will still be protected after your shot(s). Plus, the CDC says that it takes a few weeks for the body to build immunity after you get the vaccine. Regardless of what’s going on in your life right now, you’ll want to keep this in mind. In other words, even if you have the healthiest habits, it doesn’t mean you can take unnecessary risks like attending big gatherings out of the assumption that you’re fully protected, as you may expose yourself to the virus during the window when your body is building this vaccine response. Likewise, if you’re going through a particularly fraught time and you know your sleep and stress are not in the right place now, it does not mean you should avoid or wait to get an appointment until things calm down. The best thing you can do for your immune system right now is to get that vaccine. RELATED: 6 Dangerous COVID-19 Remedies to Avoid