The BOOSTED (Booster Options Or Switching Tested for Effectiveness and Downsides Study) Trial (COVID-19)

Participants assigned to this intervention will be given the recommendation to receive the Moderna vaccine for their Covid-19 booster shot. The study team will not be administering vaccines to the participants; participants must have equal access to both the Pfizer and Moderna booster vaccines to be eligible for this study. According to current FDA recommendations, Moderna booster (0.25 mL) may be administered as a heterologous booster dose following completion of primary vaccination with another authorized or approved COVID-19 vaccine. The dosing interval for the heterologous booster dose is the same as that authorized for a booster dose of the vaccine used for primary vaccination.

Participants assigned to this intervention will be given the recommendation to receive the Pfizer vaccine for their Covid-19 booster shot. The study team will not be administering vaccines to the participants; participants must have equal access to both the Pfizer and Moderna booster vaccines to be eligible for this study. According to current FDA recommendations, the Pfizer booster (0.30 mL) may be administered as a heterologous booster dose following completion of primary vaccination with another authorized or approved COVID-19 vaccine. The dosing interval for the heterologous booster dose is the same as that authorized for a booster dose of the vaccine used for primary vaccination.