You will have the most effective protection about two weeks after your final dose. In total, it can take about six weeks (from first dose to second) to become completely protected from COVID-19 after vaccination. The Pfizer and Moderna vaccines are only fully effective if you get both doses. If you only get one dose, you may not be fully protected against COVID-19, but you may still benefit from added protection. The Johnson & Johnson vaccine only requires one dose.
No vaccine or medicine can offer 100% protection, but they are worthwhile and easy methods of protection. While breakthrough cases are emerging in vaccinated people due to the Delta variant or other factors, statistics show that the vaccines are working. The CDC reports that vaccinated people with breakthrough COVID cases experience less serious symptoms, and are statistically less likely to become hospitalized or die.
Last Reviewed: 8/20/21