Consider a recent study carried out by the Centers for Disease Control and Prevention (CDC) of the authorized vaccines. Pfizer-BioNTech and Moderna's vaccines were found to be 82 percent effective after one dose in preventing people from getting Covid-19 cases with symptoms.
The Pfizer-BioNTech Covid-19 vaccine demonstrated 52 percent efficacy in protecting against disease after the first dose, according to the clinical trial data. The Moderna vaccine demonstrated 80.2 percent efficacy after the first dose. To maximize the protection from these vaccines, it is important to get both doses.
The Johnson & Johnson vaccine was 85 percent effective in preventing severe disease across all regions studied, and showed protection against COVID-19 related hospitalization and death, beginning 28 days after vaccination, according to existing data.
Learn more about vaccine efficacy here.