Adaptive immune cells are involved in the second part of an immune response. “These are special cells that respond to ‘mop up’ the remainder of the organisms left after the innate immune response,” he explains. Here comes the interesting part: The adaptive immune system has what’s known as “immune memory,” meaning that when those cells see a pathogen that has previously entered the body, not only do they help get rid of the invader, they also make more copies of themselves to continue to build a stronger defense in the future so the body is better prepared to fight off the pathogen if and when it reappears, says Starnbach. This can happen even when you don’t get ill from the germs or virus. For example, exposure to the flu can still help strengthen your immune system, even if you don’t catch it, says Eili Klein, PhD, an associate professor of emergency medicine at Johns Hopkins Medicine in Baltimore and a fellow at the Center for Disease Dynamics, Economics, and Policy in Washington, DC. “That exposure helps your immune system make antibodies that ‘remember’ the virus and how to attack it,” he explains. That’s a big reason why an older adult is more vulnerable to infection than a younger adult — because there is a faster waning of their antibodies, he says. “That’s why older people are more likely to get the flu — their immune system doesn’t work as well,” says Dr. Klein. When a new virus appears, as was the case when SARS CoV-2 (the virus that causes COVID-19) first began to spread, no one had a heightened response to it, because no one’s immune memory had encountered it, says Starnbach. That left more of us susceptible to being infected, he adds. But it’s worth noting that a vaccine isn’t a boost to our whole immune system. A flu shot doesn’t make you more resistant to colds and other illness; it boosts your immune response to the specific strains of the flu that the vaccine was designed to protect you from. “A vaccine is very specific and designed to fight off a particular pathogen such as chicken pox, polio, or the flu,” Starnbach says. A new kind of vaccine emerged during the pandemic — messenger RNA vaccines, or mRNA vaccines — and they work differently from the vaccines that preceded them. Rather than using a version of the virus to get the body to be able to recognize and mount an immune response, the Pfizer-BioNTech and Moderna COVID-19 vaccines work by introducing a piece of mRNA that corresponds to a viral protein. The vaccine “teaches” cells how to make proteins that will trigger an immune response. RELATED: Is an mRNA Flu Shot on the Way?
How Vaccines Can Protect You Against Certain Diseases and Prevent Others Altogether
Polio, hepatitis, measles, mumps, varicella (chicken pox vaccine), and the flu are other diseases that children in the United States get vaccinated against. RELATED: What You Need to Know About COVID-19 Vaccines It’s recommended that people age 50 and over get the shingles vaccine, which protects against shingles and complications related to the disease. Adults older than 65 should get the pneumococcal polysaccharide vaccine (PPSV23), which protects against serious pneumococcal disease, including meningitis and bloodstream infections. Although it’s the exception rather than the rule, there are some cases where an individual should not get certain vaccines that are recommended or required for most healthy people. This may be for reasons such as age, health conditions, or other factors. Usually, you’ll be aware of this because of conversations with your healthcare provider, but if you aren’t sure, check in with your doctor. “Our immune systems are very finely tuned,” he explains. The different immune cells are geared to recognize things in our bodies that are potentially harmful and to clear out those things. Some researchers have investigated whether supplements with specific vitamins and nutrients protect against colds and viruses, but the data suggest that if supplements are helpful they may do more in the way of reducing the severity of an infection or illness once you catch it rather than preventing it in the first place. So what can you do to protect yourself against the coronavirus and other germs? First of all, focus on preventing exposure to and the spread of pathogens, says Yufang Lin, MD, an integrative internal medicine doctor at Cleveland Clinic in Ohio. “Wash your hands, and if you cough or sneeze, do so into a tissue and throw that tissue away,” she says. The other part of the equation is to practice health-promoting behaviors that keep your own immune system functioning at its best (and that help prevent underlying chronic health problems that ultimately do make you more susceptible to infections), according to Dr. Lin and Starnbach. More specifically: RELATED: An Immunology Expert Shares What She Eats in Day
Manage your stress. Stress can suppress the immune system, keeping it from working at 100 percent. “Try to take time to relax and do something fun,” Lin says. “Make sure you take care of yourself.”
Experts don’t know why autoimmune diseases occur; they aren’t contagious. There is a hereditary link for many autoimmune conditions, and it may be that a virus or an environmental factor triggers the disease if a person already has the genes for it. Smoking Smoking suppresses your immune system and weakens your lungs, so people who smoke are more susceptible to pneumonia or a viral infection, Lin says. Medications Some drugs can keep your immune system from functioning the way a healthy person’s would, says Lin. “Immunomodulators, steroids, or medications for autoimmune conditions can suppress your immune system,” she says. Age Young children can be more susceptible to catching viruses because their immune systems are still developing; it’s part of the maturation process, Lin says. As they grow older, children’s immune systems are exposed to different viruses, they become accustomed to being exposed to more viruses, and they become much more able to fight those off. “But when they are very young, every time [children] see a new pathogen their body is mounting a significant response,” Lin says. Older people, too, tend to have weaker immune systems than other groups. Older people can have multiple chronic medical problems, says Lin. If the body is constantly dealing with a variety of medical conditions, that can make it harder to fight off a virus. “Along with that, as we get older our immune system gets a little bit weaker, and it can take longer for our bodies to mount a significant immune response when we get sick. That gives the virus or infection more time to grow or to replicate, which could lead to more severe symptoms,” says Lin. Underlying medical conditions Preexisting chronic medical conditions, like asthma, diabetes, and heart disease, can affect the immune system and put people with these conditions at higher risk of infections. Pregnancy Pregnant women experience changes in their immune system and body that may place them at higher risk of viral infections, says Lin. Just by being pregnant your immune system is somewhat stretched, because it is taking care of two rather than just one, she adds. Malnutrition People who are malnourished are more susceptible to viruses and certain diseases, Starnbach says. Deficiency in certain vitamins and minerals in the body keeps the immune system from functioning optimally. Replenishing those missing nutrients with supplements can help the immune system function in a healthy way and better ward off diseases and infections. But whether or not supplements help improve immune response generally or in specific ways in people who are not deficient in vitamins and nutrients is less clear. RELATED: Do Probiotics Help Your Immune System?
