As of now, there isn't any evidence that people will need a COVID-19 booster dose, according to the Advisory Committee on Immunization Practices (ACIP), an independent group of advisers to the Centers for Disease Control and Prevention.
The committee gave a presentation to the CDC Wednesday to look at a number of questions surrounding boosters, including whether they will be necessary and only for specific groups. Its conclusion was that the committee would only recommend people get booster shots if two conditions were met:
- If there were evidence showing a drop in protection against illness from COVID, like if vaccine effectiveness dropped, and,
- If an "escape" variant of the virus impacted protection from the vaccines.
As of right now, there's evidence of neither of those, the group found. But, the committee says it will continue to monitor the situation, which could mean booster shots would be recommended down the road. Even then, however, there may only be certain people who need booster shots, such as those over age 65 or people who are immunocompromised.
There are many other factors to consider as well. For example, according to the presentation, certain studies have shown that after the initial vaccine dose or doses, people with compromised immune systems may have a limited antibody response to a booster shot.
Most of this leaves scientists with more questions than answers at this point. ACIP says that it is expecting more data from vaccine manufacturers in the coming months on the safety of booster doses, and even data on whether people will be able to "mix-and-match" vaccines, should a booster shot become necessary.