* A 3- to 4-week interval between primary series doses was studied in the registration trials. Healthy individuals <65 years old can extend the interval to 8 weeks; this approach may be preferable for young adults (especially males 18 to 39 years old) who do not need to maximize protection within a shorter period of time.
¶ If possible, the same vaccine formulation should be used to complete the primary series. If the original vaccine is not available or if the patient has developed a contraindication to that vaccine, a different, age-appropriate COVID-19 vaccine can be used to complete the primary series; in such cases, the second dose is given at least 4 weeks after the first.
Δ If the patient received monovalent booster doses in addition to the primary series, a single booster dose of a bivalent vaccine is still recommended at least 2 months following the most recent monovalent vaccine dose.
For individuals 18 years or older who have received a primary vaccine series but no prior booster dose and are unable or unwilling to receive an mRNA vaccine, a single dose of NVX-CoV2373 can be used as a booster dose at least 6 months after the last primary series dose.