No single COVID-19 vaccine brand is clearly superior for adults over 65. The CDC recommends all three available options for this age group: Moderna, Pfizer-BioNTech, and Novavax. What matters more than brand choice for seniors is getting two doses per year instead of one, since adults 65 and older are the only age group specifically recommended to receive that second dose.
Your Three Options
Moderna and Pfizer-BioNTech are both mRNA vaccines, meaning they instruct your cells to produce a small piece of the virus’s surface protein so your immune system learns to recognize it. Novavax takes a different approach: it delivers that protein directly, paired with an ingredient that boosts your immune response. This protein-based method has been used in vaccines for decades, including hepatitis B and shingles shots.
In clinical trials, Novavax showed 90.4% effectiveness overall at preventing COVID-19, but that number dropped to 78.6% in the subgroup of participants aged 65 and older. Moderna and Pfizer produced similar overall efficacy in their original trials. The real-world numbers that matter now, though, come from more recent data against current variants, and those numbers are comparable across brands.
If you had a reaction to an mRNA vaccine in the past or simply prefer a more traditional vaccine technology, Novavax is a reasonable alternative. Otherwise, any of the three will do the job.
How Well the Current Vaccines Work for Seniors
CDC data from September 2024 through January 2025 measured how well the updated vaccines prevented hospitalization in adults 65 and older. For seniors with healthy immune systems, vaccine effectiveness against COVID-related hospitalization was about 45% to 46% within the first four months after vaccination. That number held steady whether measured at one month or three months post-vaccination.
For seniors with weakened immune systems, effectiveness was slightly lower at around 40%. These numbers reflect protection against hospitalization specifically, not mild infection. Hospitalization rates during this period were low enough that researchers couldn’t separately estimate protection against ICU admission or death, but preventing hospital stays alone is significant for this age group.
A 45% reduction in hospitalization risk may sound modest compared to the 90%-plus figures from early in the pandemic, but today’s variants have shifted substantially. That level of protection still translates to thousands of prevented hospital admissions among older adults each season.
Why Seniors Need Two Doses a Year
Starting in late 2024, the CDC specifically recommended that adults 65 and older receive two doses of the updated COVID vaccine, spaced about six months apart. This makes seniors the only general age group advised to get more than one dose per season. The reason comes down to how aging changes the immune system.
As you get older, your immune system gradually becomes less responsive to vaccines. Your body produces fewer of the immune cells that “remember” a virus after vaccination, and the antibodies it does produce tend to be less effective at neutralizing new variants. There’s also a background level of chronic inflammation that increases with age, which paradoxically blunts the immune system’s ability to mount a strong, targeted response to a vaccine.
The practical result: protection from a single dose fades faster in older adults than in younger people. A second dose six months later restores that waning protection. For people who are moderately or severely immunocompromised, a third dose or more may be appropriate based on discussion with a healthcare provider.
Timing and Spacing Your Doses
If you’ve received any previous COVID vaccine (from any year or manufacturer), you’re eligible for two doses of the current formulation. Your first dose should come at least eight weeks after your last COVID shot if you’re getting Pfizer, Novavax, or standard Moderna. Moderna’s newer low-dose formulation (mNexspike) requires a minimum of three months since your last dose.
The second dose is recommended six months after the first, though the minimum interval is two months for Pfizer, Novavax, and standard Moderna, or three months for the low-dose Moderna. You don’t need documentation of previous vaccinations to get your shots. Self-reporting your vaccine history is sufficient, and pharmacies and clinics should not turn you away for lack of records.
Getting COVID, Flu, and RSV Shots Together
Many seniors are now candidates for three respiratory virus vaccines: COVID, flu, and RSV. All three can be given during the same visit, which is convenient but comes with a tradeoff. Limited data suggest that getting an RSV vaccine at the same time as other respiratory vaccines may result in a somewhat lower antibody response, though it’s unclear whether that translates to less real-world protection. You’re also more likely to experience common side effects like injection-site pain, headache, muscle aches, and low-grade fever when receiving multiple vaccines at once.
If you’d rather minimize side effects or want to ensure the strongest possible immune response from each shot, spacing them out by a few weeks is reasonable. But if getting them all in one trip is the difference between getting vaccinated and not, doing them together is the better choice.
Side Effects in Older Adults
Severe side effects from COVID vaccines are rare in adults over 65. In a study of nearly 1,000 vaccinated older adults (average age around 69), most reported mild or no side effects. The most common reactions are the same ones younger adults experience: sore arm, fatigue, headache, and mild fever, typically lasting one to two days.
One finding worth noting: among the small number of older adults who did experience severe side effects, there was a meaningful link to depressive symptoms. Those who reported three or more severe side effects were about seven times more likely to also report significant depressive symptoms. This doesn’t mean the vaccine caused depression, but it suggests that if you’re already managing mood concerns, being prepared for a rough day or two after vaccination can help you plan accordingly.
Vaccination and Long COVID Risk
Beyond preventing hospitalization, vaccination appears to reduce the risk of developing long COVID. A systematic review of 12 studies found that people vaccinated before infection had lower odds of long-lasting symptoms. Two doses of vaccine before infection were associated with odds ratios as low as 0.25, meaning vaccinated individuals were up to 75% less likely to develop long COVID compared to unvaccinated people. Three doses showed an even stronger signal, with one study finding an 84% reduction.
Even getting vaccinated after a COVID infection showed benefit: studies reported 9% to 62% lower odds of persistent symptoms, and some found that vaccination improved recovery rates in people already experiencing long COVID. The overall evidence quality is low due to study design limitations, but the pattern is consistent enough to be meaningful, particularly for older adults who are already at higher risk of prolonged illness.