If you’re looking for a COVID booster right now, the most current option is the 2024-2025 formula, which targets the JN.1 lineage of Omicron (specifically the KP.2 strain). The earlier 2023-2024 boosters, which targeted the XBB.1.5 subvariant, are no longer available. Three manufacturers produce updated vaccines: Moderna, Pfizer-BioNTech, and Novavax. There is no official preference for one over another, so the best booster is whichever one you can get.
What’s in the Current Vaccines
All three available COVID vaccines have been reformulated to match circulating variants, similar to how flu shots are updated each year. The 2024-2025 versions target the JN.1 lineage and its descendants. The FDA’s advisory committee initially recommended a JN.1 composition, then refined that preference to the KP.2 strain based on surveillance data showing it more closely matched what was spreading across the country.
Moderna and Pfizer-BioNTech both use mRNA technology, where the vaccine delivers genetic instructions that teach your cells to produce a piece of the virus’s spike protein, triggering an immune response. Novavax takes a different approach: it delivers the spike protein itself, grown in a lab, along with an ingredient that boosts the immune response. Both methods train your immune system to recognize and fight the virus, but they get there differently.
How the Three Options Compare
For most people, the practical differences between the three vaccines are minimal. Research shows that all three generate strong immune responses against circulating variants. One immunology study found that mRNA vaccines may produce slightly stronger long-term immune memory from a specific type of immune cell (CD8 cells), which plays a role in killing infected cells. Novavax, on the other hand, showed a shift toward a different type of immune memory (CD4 cells) over six months. In real-world terms, though, all three protect against severe illness, hospitalization, and death.
Novavax has been chosen by far fewer people overall. In Germany, for example, fewer than 2% of all COVID vaccine doses administered were the protein-based option. That smaller track record means less data on rare side effects, but it offers a non-mRNA alternative for people who prefer a more traditional vaccine technology.
Who Should Get One
The CDC recommends the updated COVID vaccine for everyone aged 6 months and older. That said, guidance shifted in May 2025: for healthy children and adolescents aged 6 months through 17 years, vaccination moved to “shared clinical decision-making,” meaning parents and providers weigh the individual child’s risk factors rather than following a blanket recommendation. The benefit is considered most favorable for people at higher risk of severe COVID, including older adults and those with underlying health conditions.
For immunocompromised individuals, the schedule is more involved. After completing an initial series, additional doses may be given at least 2 months apart, based on a conversation with a healthcare provider. Children aged 6 months through 4 years who haven’t received any COVID vaccine need a multi-dose initial series: three doses for Pfizer-BioNTech or two for Moderna. Everyone aged 5 and older needs just one updated dose, regardless of how many previous shots they’ve had.
Timing After a Recent Infection
If you recently tested positive for COVID, the CDC says you can delay your vaccine by 3 months from when symptoms started, or from the date of a positive test if you had no symptoms. This isn’t a hard rule. You’re allowed to get vaccinated sooner, but waiting gives your natural immune response time to provide protection on its own, and some evidence suggests the vaccine works better with that gap.
Side Effects to Expect
The side effect profile for the updated boosters is consistent with what earlier COVID vaccines produced. Pain at the injection site is the most commonly reported reaction. Systemic effects, meaning those felt throughout the body, include fatigue, headache, muscle aches, joint pain, and chills. One large study of hospital employees found that about 84% reported at least one symptom after a booster dose, compared to 79% after a first dose. Most symptoms resolve within a day or two.
Fever is also common. A multicenter study found that after a first dose, injection site pain and fever each occurred in roughly 70% of recipients. Booster doses tend to produce similar or slightly more noticeable reactions, likely because your immune system recognizes the spike protein and mounts a faster response.
Getting It With Your Flu Shot
You can receive a COVID vaccine and a flu shot during the same visit. Studies support the safety of co-administration, and there’s no recommended waiting period between the two. Getting both at once saves a trip and makes it easier to stay current heading into respiratory virus season.
Cost and Availability
COVID vaccines remain free for most Americans. The insurance industry trade group AHIP announced that all recommended immunizations, including updated COVID and flu vaccines, will be covered with no out-of-pocket cost through the end of 2026. This applies to private insurance plans. Medicare also covers the vaccines. If you’re uninsured, availability and cost may vary by location, so checking with local pharmacies or community health centers is your best bet.
Which One to Pick
The CDC does not recommend one vaccine brand over another when more than one age-appropriate option is available. If you have a strong preference for avoiding mRNA technology, Novavax is the protein-based alternative, though it’s approved only for ages 12 and up. Moderna is available for ages 6 months and older, and Pfizer-BioNTech for ages 5 and up. In practice, your choice often comes down to which vaccine your pharmacy has in stock. Any of the three, given on time, does the job it’s designed to do: reduce your risk of severe COVID.