Could we soon be rolling up our sleeves for a fourth COVID-19 vaccine shot?

The Centers for Disease Control and Prevention has not recommended another dose just yet, but some doctors say it seems likely – especially as the vaccine's effectiveness goes down over time.

The CDC released a new study last week on the vaccine effectiveness after the third dose. It showed that effectiveness went down from 91% to 78% protection four months after getting the booster.

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Other countries, such as Israel and Sweden, have both started giving out a fourth dose of the mRNA vaccine. Doctors say results there will be informing the decisions made in the U.S.

An FDA official also suggested a fourth dose of the COVID-19 vaccine might be needed closer to fall – when residents usually line up for the flu shot.