While infection does contribute to the immune “library,” modern vaccines offer a safer, more reliable way to add to that protection without the risks of serious illness, hospitalization or long-term complications.

As flu activity increases across the U.S. this winter, experts emphasize that vaccines remain one of the strongest tools for maintaining health and preserving natural immunity over a lifetime.

Vaccine decisions start with informed conversations

“Vaccination is an individual decision, but the impact of the vaccine protects both the individual and their family cohort, work cohort. If they're in school, it can protect that community,” says Doug Kasper, MD, infectious disease specialist with OSF HealthCare. “We want people to be as educated as possible and make the best decision for themself. That's really going to come down to a discussion with them and their medical provider.”

For older generations who remember “just getting the measles,” today’s medical guidance recognizes that while infection can create immunity, it also carries significant risks – and vaccines provide a much safer pathway to the same immune protection.

How flu vaccines strengthen natural immunity

“Flu vaccines, historically, never match up perfectly to all the influenza strains that circulate in the community. What we do know is that immunity is cumulative; it's a library across a person's life and it has all of their prior infections and vaccines. It builds up over time,” Dr. Kasper says.

He explains that vaccines support and expand your natural immune memory.

“Receiving a seasonal flu vaccine, while the protection it may provide in any year may be different; over time there are benefits to doing this activity, so that you have a robust variety of immunity. As the seasonal infections change, you may be protected from something that happened in the past.”

This means vaccines don't replace natural immunity – they contribute to it, adding layers of defense that reduce the severity of illness and strengthen long-term protection.

Why vaccines remain a powerful community tool

Vaccines benefit individuals, but they also help stabilize the entire health system.

“When we talk about vaccination, we talk about it at a population level. We would like every individual to not get sick, but we also know that with hospitals, urgent cares and emergency departments, that we are trying to keep the system functional,” Dr. Kasper says. “We do that by getting as few people sick as possible, and vaccines are a very useful tool to help the individual help their community and help the medical system.”

A season of multiple circulating viruses

As families enter the stretch leading up to Christmas, flu activity is increasing on both coasts – often a preview of what will soon reach the Midwest.

COVID-19 continues to circulate year-round, RSV season is underway and Central Illinois is just beginning to see early influenza activity. Early surveillance suggests this year’s flu vaccine may not be a perfect match, but even imperfect vaccines help reduce severity, hospitalizations and complications. They also continue contributing to the “immune library” that protects people long-term.

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We’re approaching the late summer-early fall period when respiratory illnesses begin their annual upswing. The latest news from federal health officials concerns a new variant of COVID-19, NB.1.8.1. Some people impacted have reported severe sore throats, almost like there’s a razor blade in there.

Fred Burke, MD, an emergency medicine physician who sees patients at OSF HealthCare, says illnesses like COVID, RSV and the flu will always be around. It’s just a matter of taking precautions to avoid serious illness. So, what’s the level of concern with this new COVID variant as we begin to make fall plans?

The razor’s edge

Any sore throat is an annoyance. But Dr. Burke says you should monitor severe cases closely.

“You’re less likely to want to eat or drink, which can lead to further dehydration,” he says.

You can manage sore throats at home with Tylenol or ibuprofen, chloraseptic spray, warm tea and throat lozenges. Dr. Burke says if you have trouble keeping food or fluids down, feel lightheaded or dizzy or have trouble breathing, see a health care provider right away.

COVID precautions

Dr. Burke says this new COVID variant isn’t linked to as much severe illness as other variants. But, he says it’s more easily spread.

“The average healthy person might get through it with some [figurative] bumps and bruises and little to no symptoms. For people with comorbidities or who are immunocompromised, the virus might be a little bit more detrimental,” Dr. Burke says.

Getting vaccinated and practicing good hygiene are two big tools to avoid serious illness, he adds. Wash your hands and high touch surfaces, like doorknobs, often, don’t cough or sneeze into the open air and stay home and away from others when you don’t feel well. If you’re in a crowd, especially if you have a comorbidity like diabetes, Dr. Burke says you should consider wearing a mask.

“If you’re going to have a gathering, whether at home or somewhere else, you can also recommend people take a home test to make sure they don’t have COVID prior to going,” Dr. Burke suggests. Those at-home tests can usually be found over the counter at a pharmacy.

For vaccines, recent preliminary guidance from the U.S. Food and Drug Administration recommends the shot this fall for people 65 and up. For others, the shot is recommended for people who have a compromised immune system or a comorbid condition like obesity, heart disease, high blood pressure, lung disease or depression. The website for the U.S. Centers for Disease Control and Prevention, meanwhile, has a broader recommendation. When in doubt, Dr. Burke says to talk to your primary care provider.

Learn more

Explore other resources to keep yourself safe from COVID on the OSF HealthCare website, blog and newsroom.

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The updated COVID-19 vaccine is expected to be available at pharmacies around the country in the coming weeks. 

The mRNA vaccine is not a booster, says Doug Kasper, MD, an infectious disease specialist with OSF HealthCare. He says it's recommended  for a much broader portion of the population, everyone six months and older, as a one-time, once a year vaccine. 

This vaccine does not prevent you from getting COVID-19, but the goal is to prevent severe illness from the virus. 

Dr. Kasper says it's totally fine to get the COVID-19 and flu vaccines in the same appointment.

"There's no issue with timing on getting the COVID and influenza vaccines. The RSV vaccine is recommended to be given separate," Dr. Kasper says. "Most of that has to do with the fact they weren't studied together, there's not an adverse issue with it. For the population, COVID and influenza are recommended across almost all age groups. RSV is for our older population, so we recommend spacing that out by a week or two."

Dr. Kasper says for those 65 and older with respiratory conditions, it might be recommended they receive a second booster in six-month increments.

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