The CDC recommends a single-dose COVID-19 vaccine booster for all adults ages 18 years and older. Those who initially acquired the Pfizer/BioNTech or Moderna mRNA vaccine can get their booster 5 months after their second shot, and folks who acquired an preliminary dose of the Johnson & Johnson vaccine can get a booster dose two months after their initial vaccine. Adults could choose any vaccine for their booster, either the identical or completely different than their initial vaccine. However, the CDC has said a desire for either of the mRNA vaccines over the Johnson & Johnson vaccine. The CDC recommends that children ages 5 to 17 years receive the two-dose Pfizer/BioNTech COVID-19 vaccine.