Adults 65 and older and people with moderate to severe immune compromise are recommended to get a second dose of the current COVID-19 vaccine six months after their first updated dose. For most other people, a single annual updated dose is the standard recommendation. Here’s how to figure out where you fall and when to schedule yours.
Who Qualifies for a Second Dose
In October 2024, the CDC’s Advisory Committee on Immunization Practices established two groups that should receive a second dose of the updated COVID-19 vaccine:
- Adults 65 and older: All adults in this age group are recommended to get a second dose, regardless of their overall health.
- People ages 6 months to 64 with moderate or severe immune compromise: This includes people actively being treated for cancer, those with blood cancers that weaken vaccine response, solid organ or islet transplant recipients on immunosuppressive therapy, people who’ve had CAR-T cell therapy, bone marrow transplant recipients within the past two years, people with significant primary immunodeficiency, those with advanced or untreated HIV, and people taking certain immunosuppressive medications.
If you’re under 65 and have a healthy immune system, the current guidance calls for one dose of the updated vaccine per season. You don’t need a second dose.
Timing and Minimum Intervals
The recommended interval between your first updated dose and your second is six months. If circumstances require it sooner, the minimum allowable interval is two months, though waiting the full six months provides the best balance of protection and immune response.
For people who are immunocompromised, the math works the same way: six months is ideal, two months is the minimum. After that second dose, additional doses may be an option in consultation with a healthcare provider, with at least two months between each one. This flexibility exists because people with weakened immune systems often mount a weaker response to vaccination and may benefit from repeated boosting.
Why Protection Fades Over Time
The rationale for a second dose comes down to how quickly vaccine effectiveness drops. Within six to eight months of a single mRNA booster, protection against any COVID-19 infection falls to roughly 14%, while protection against severe illness drops to about 68%. A second booster restores some of that lost ground, though protection still declines again over the following months, settling around 30% for infection and 71% for severe disease within five to seven months.
For older adults and immunocompromised people, that gap between “some protection” and “fading protection” matters more. These groups face higher rates of hospitalization and complications from COVID-19, so maintaining stronger protection through the winter months can make a meaningful difference.
What to Expect From Side Effects
If you had side effects from your first booster, you can expect a similar experience the second time around. In a study published in The Lancet Respiratory Medicine, about two-thirds of participants reported no side effects at all after their second booster. Among those who did, the most common reactions were fatigue, headache, muscle pain, cold-like symptoms, and sore throat. Nearly all of these resolved within three days.
Importantly, the second booster does not appear to cause worse reactions than the first. People who had stronger side effects from earlier doses tended to report similar intensity the second time, but not greater. There was no increased risk of serious adverse events compared to the first booster.
If You Recently Had COVID-19
A recent infection changes your timing. If you tested positive, wait at least 10 days from when symptoms started before getting vaccinated. If you tested positive without symptoms, count 10 days from the date of your positive test. There’s no benefit to waiting longer than that.
One exception: if you were treated with monoclonal antibodies or convalescent plasma during your infection, wait at least 90 days before getting your dose. These treatments contain antibodies that can interfere with the vaccine’s ability to train your immune system.
Some people also choose to wait a bit longer after infection since the illness itself provides temporary immunity. This is a reasonable approach, but there’s no official recommendation to delay beyond the 10-day or 90-day windows described above.
Vaccination During Pregnancy
COVID-19 vaccination is recommended at any point during pregnancy. The vaccine can protect against severe illness during a time when your body is already under significant strain, which in turn protects your baby. The same applies if you’re breastfeeding. No special timing adjustments are needed for pregnant or breastfeeding individuals beyond the standard intervals.
The 2025-2026 Updated Vaccine
Starting in fall 2025, the FDA has directed manufacturers to produce a new formulation targeting the JN.1 lineage of the virus, preferentially using the LP.8.1 strain. This is a single-strain (monovalent) vaccine designed to better match the variants currently circulating. If you haven’t yet received your second dose of the 2024-2025 vaccine and the new formulation becomes available, your provider can help you decide whether to finish out the current schedule or transition to the updated version.
For previously vaccinated individuals ages 12 to 64, the recommended interval before getting the 2025-2026 dose is at least eight weeks after the last dose for most vaccines, or at least three months for the Moderna mNexspike formulation.
How to Find a Dose Near You
The CDC’s Vaccines.gov website lets you search by ZIP code to find pharmacies offering COVID-19 vaccines near you. Enter your location, choose a pharmacy from the results, and contact them directly to confirm availability and schedule an appointment. Most major pharmacy chains, community health centers, and some primary care offices carry the updated vaccine.