In the years-long battle against COVID-19, one fact has become crystal-clear: Older adults face a much higher risk of severe illness and complications from the virus (SARS-CoV-2). This is especially true for those who haven’t received one of the available COVID vaccines.

But why does age make us more vulnerable to serious COVID disease? Let’s look at the factors behind this increased risk—and how vaccination can help older adults stay healthy and out of the hospital.

Why does COVID affect older adults more?

There are four primary reasons older Americans are more likely to get infected with COVID and experience worse health outcomes:

1. Weakened immune system: As we age, our natural defenses against infections weaken—a process known as immunosenescence. During this process, the immune system becomes less effective at identifying and fighting off viruses like SARS-CoV-2 and building protective immunity.

How vaccination helps: Vaccination plays a crucial role by strengthening the natural immune response. mRNA vaccines, for example, use special technology to trigger our immune system to produce COVID antibodies, which linger in our body for many months. If we’re exposed to COVID in the future, these antibodies help our immune defenses recognize and attack the virus. Without vaccination, older adults lack this critical boost, leaving their already-compromised immune system at a disadvantage.

2. Greater risk of severe outcomes: Older adults are more likely to get COVID if they’re unvaccinated, and they’re also at higher risk for severe outcomes like hospitalization and death. Studies have shown the risk of serious complications from COVID increases with age. In fact, according to the Centers for Disease Control and Prevention (CDC), 67% of COVID hospitalizations occurred in people over age 65 in the period October 2023 to May 2024.¹ More than 95% of adults hospitalized due to COVID in 2023-2024 had no record of receiving the latest vaccine.² In addition, people age 75 and older were roughly nine times as likely to die from COVID compared to adults age 18-39.³

The severe impact of COVID on older adults is partly due to the body’s less robust response to infection. However, age-related inflammation in the body (called inflammaging) also plays a role. This long-term inflammation can affect the way SARS-CoV-2 progresses in the body, worsen COVID symptoms, and make recovery from the virus more challenging. Inflammaging also makes us more vulnerable to diseases such as cancer, cardiovascular disease, dementia, and osteoporosis.

How vaccination helps: The COVID vaccine empowers our immune system to fight off the virus before it can lead to severe complications. For instance, a new study found that full vaccination against COVID can reduce the risk of COVID-related cardiovascular disease by 20-30% compared to not being vaccinated.⁴ Getting vaccinated can also help prevent long COVID, which is when severe and often debilitating COVID symptoms last for weeks and months after the initial infection has passed. Research shows that a person's risk of developing long COVID is lower if they’ve received the vaccine.⁵

3. Underlying ongoing health conditions: Many older adults live with health conditions such as heart disease, obesity, diabetes, neurocognitive disorders, and kidney disease. These conditions can further strain an immune system already weakened by age and cause more severe COVID illness. “So, all those comorbidities added to the phenomena of waning immunity as you age leads to you getting an outsized physical manifestation, which is much more severe if you compare it to a younger, healthier individual," Devang Sanghavi, MD, a Florida-based intensivist and medical director, told the American Medical Association.

How vaccination helps: Vaccination can be especially protective for older adults with chronic conditions, as it lowers the chances of serious complications if they do get COVID. And even when breakthrough cases occur, symptoms tend to be milder than cases in people who are unvaccinated.

4. Higher exposure potential in certain settings: In the early days of the pandemic, nursing home residents made up a large percentage of COVID-related deaths. That’s because in these communal living environments, close contact with others can cause the virus to spread like wildfire. Even with strict safety measures in place, it’s nearly impossible to eliminate exposure risk—especially if some residents aren’t vaccinated.

How vaccination helps: Vaccination adds a powerful layer of protection in high-risk residential environments. By getting vaccinated, older adults reduce their risk of getting COVID, even if the virus is circulating in their facility or the broader community. What’s more, vaccinated people are less likely to spread the virus to others—and that helps create a safer environment for everyone, including facility staff and visitors.

Are COVID shots safe for seniors?

The COVID vaccines available today have been rigorously tested for safety through multiple phases of clinical trials. This includes mRNA vaccines, which use well-studied technology to help the body create a strong defense against SARS-CoV-2. Both mRNA vaccines, approved by the U.S. Food and Drug Administration (FDA), are recommended by CDC with an emphasis on adults age 65 and older. After testing and approval, data on vaccines continues to be collected by the FDA and CDC to monitor their safety and effectiveness, including the COVID vaccines.

Other benefits of mRNA benefits for older adults include:

• Strong protection: Early clinical trials for the two COVID mRNA vaccines showed a more than 90% efficacy rate in preventing infection and high efficacy in preventing severe disease, hospitalization, and death.⁶ This level of protection can mean the difference between a mild, manageable infection and a life-threatening one.
• Fewer side effects: Older adults can be more sensitive to the side effects of traditional vaccines. Side effects for mRNA vaccines tend to be mild and temporary (e.g., soreness at the injection site or tiredness, and muscle aches).
• Adaptability to different pathogens: As COVID continues to mutate, mRNA technology allows scientists to quickly update the vaccine formula to target new variants—so older adults can stay protected against the latest circulating strains.

Where can I get a free COVID vaccine near me?

You can find vaccination sites near you by visiting Vaccines.gov. All recommended immunizations for older adults are now fully covered by Medicare and Medicaid. That means you should pay nothing out of pocket at your next vaccination appointment.

Set a healthy example for others by rolling up your sleeve to get your updated COVID and flu shots. Both mRNA COVID vaccines and the flu vaccine have been reformulated for 2024-2025 (see CDC guidance). Even better? You can get your COVID and flu shots at the same time and be dually protected as cold and flu season kicks into high gear.

Sources

1. Centers for Disease Control and Prevention (CDC) National Center for Immunization and Respiratory Diseases. COVID-19–Associated Hospitalizations Among Children and Adults: COVID-NET. Found on the internet at https://www.cdc.gov/acip/downloads/slides-2024-06-26-28/02-COVID-Havers-508.pdf

2. Centers for Disease Control and Prevention (CDC) - Respiratory Illnesses. Respiratory Viruses and Older Adults. Found on the internet at https://www.cdc.gov/respiratory-viruses/risk-factors/older-adults.html

3. Centers for Disease Control and Prevention (CDC) – COVID-19. Underlying Conditions and the Higher Risk for Severe COVID-19. Found on the internet at https://www.cdc.gov/covid/hcp/clinical-care/underlying-conditions.html

4. University of Minnesota - Center for Infectious Disease Research & Policy (CIDRAP). Study: COVID-19 vaccination protects against serious cardiovascular disease. October 1, 2024. Found on the internet at https://www.cidrap.umn.edu/covid-19/study-covid-19-vaccination-protects-against-serious-cardiovascular-disease

5. Yan Xie, PhD, et. al. Postacute Sequelae of SARS-CoV-2 Infection in the Pre-Delta, Delta, and Omicron Eras. New England Journal of Medicine. July 17, 2024. Found on the internet at https://www.nejm.org/doi/full/10.1056/NEJMoa2403211

6. National Institutes of Health (NIH). NIH Vaccine Research Center Leads the Way to Safe, Effective COVID-19 Vaccines. Found on the internet at https://covid19.nih.gov/news-and-stories/nih-vaccine-research-center