Since the first COVID-19 vaccines rolled out in December 2020, there have been six distinct vaccine formulations offered in the United States, with the newest 2025-2026 version arriving in fall 2025. But the total number of shots any one person has been eligible for depends on their age, health status, and when they started getting vaccinated. A healthy adult who kept up with every recommended dose could have received up to seven or eight shots by now, while someone just starting today needs only one.
Every COVID-19 Vaccine Formulation So Far
The simplest way to count boosters is by the distinct formulas the FDA has authorized or approved. Each time the virus evolved significantly, the vaccine was reformulated to match the circulating strains. Here’s the full timeline:
- Original formula (December 2020): The first Pfizer and Moderna mRNA vaccines, targeting the original SARS-CoV-2 strain. Most adults received two primary doses, spaced three to four weeks apart. The Johnson & Johnson single-dose vaccine was also authorized in early 2021.
- Original-strain boosters (fall 2021): A third dose of the same original formula, recommended for adults who had completed their primary series.
- Second original-strain booster (spring 2022): A fourth shot of the original formula, initially authorized for adults 50 and older and immunocompromised individuals.
- Bivalent update (fall 2022): The first reformulation, combining the original strain with Omicron BA.4/BA.5 subvariants. This was the first time the vaccine recipe changed.
- 2023-2024 update (fall 2023): A monovalent vaccine targeting the XBB.1.5 Omicron subvariant. The original strain was dropped entirely.
- 2024-2025 update (fall 2024): Reformulated to target the Omicron KP.2 subvariant. Available from Pfizer, Moderna, and Novavax.
- 2025-2026 update (fall 2025): The newest version, targeting the JN.1 lineage, preferentially using the LP.8.1 strain. Available from Pfizer, Moderna, and Novavax, with a newer Moderna formulation called mNexspike also approved.
The Johnson & Johnson vaccine was phased out and is no longer available. Novavax, a protein-based (non-mRNA) option, joined the lineup in 2022 and remains available for ages 12 and up.
How Many Shots You Actually Need Now
Regardless of how many previous doses you’ve had, or even if you’ve never been vaccinated, the current recommendation is straightforward. The CDC recommends one dose of the 2025-2026 COVID-19 vaccine for everyone ages 6 months and older. Your vaccination history doesn’t change this: one updated shot is the standard recommendation.
There are two groups who may get more than one dose of the current formula. Adults 65 and older were recommended a second dose of the 2024-2025 vaccine six months after their first, and a similar approach is expected going forward. People who are moderately or severely immunocompromised can receive additional doses at least two months apart, in consultation with their healthcare provider.
What’s Different for Young Children
Children under 5 have a more limited selection. For ages 6 months through 4 years, Moderna is the only approved option for the 2025-2026 season. Children ages 5 through 11 can receive either Moderna or Pfizer. Kids who have never been vaccinated before may need a short primary series (two doses) before they’re considered up to date, unlike older children and adults who need just one shot of the current formula.
For immunocompromised children ages 6 months through 4 years, any additional doses should be the same vaccine brand they received initially.
Why the Vaccine Keeps Changing
COVID-19 vaccines now follow a pattern similar to the annual flu shot. Each year, an FDA advisory committee meets to evaluate which virus strains are circulating and selects the best match for the upcoming season. In May 2025, the committee unanimously recommended a JN.1-lineage composition for the 2025-2026 formula. This annual update means last year’s vaccine becomes outdated, much like last year’s flu shot.
The shift to yearly updates also means the concept of “boosters” is fading. Early on, each additional shot was called a booster because it used the same formula. Now, each fall brings a reformulated vaccine designed to match the current virus, so the CDC frames it as an updated vaccine rather than a booster of the old one.
Available Vaccines for 2025-2026
Four vaccine products are approved for the current season. Moderna offers two versions: Spikevax (its established mRNA vaccine) and mNexspike (a newer formulation). Pfizer-BioNTech and Novavax round out the options. All four are available for ages 12 and up. For younger children, only Moderna’s Spikevax is approved for those under 5, while Pfizer joins the options starting at age 5.
Novavax remains the only protein-based option for people who prefer a non-mRNA vaccine. It uses a more traditional technology, pairing a lab-made version of the spike protein with an immune-boosting ingredient to trigger protection.