You can check vaccination sites in nearby ZIP codes for open appointments, or you can keep checking back because new appointments are added often. The typical interval between the first and second primary series doses is 3 weeks for Novavax or Pfizer-BioNTech and 4 weeks for Moderna, especially for anyone who is immunocompromised.
An 8-week interval between the first and second doses of Moderna, Novavax and Pfizer-BioNTech COVID-19 vaccines may be optimal for some people as it may reduce the small risk of myocarditis and/or pericarditis associated with these COVID-19 vaccines, particularly in males ages 12–39 years. Please remember that the Johnson & Johnson (Janssen) primary vaccine is only one dose.
For more detailed information, visit https://www.cdc.gov/vaccines/covid-19/info-by-product/clinical-considerations.html.