What happens if I receive the second dose after the recommended time? Do I need to start the vaccination series over?

The second dose should be administered as close to the recommended time as possible (three weeks after the first Pfizer-BioNTech vaccine dose or one month after the first Moderna vaccine dose). If for any reason you do not receive the vaccine within the recommended time interval, you can get the second dose up to six weeks (42 days) after the first dose. There is currently no data on vaccine doses given beyond this window. If you get your second dose outside of these time periods, there is no need to restart the series. Vaccine administration errors should be reported to the Vaccine Adverse Event Reporting System (VAERS).*

*https://www.cdc.gov/vaccines/covid-19/info-by-product/clinical-considerations.html