Pfizer COVID Vaccine Effective After 1st Dose, But U.S. May Face Supply Shortage - Consumer Health News | HealthDay

Pfizer COVID Vaccine Effective After 1st Dose, But U.S. May Face Supply Shortage - Consumer Health News | HealthDay: TUESDAY, Dec. 8, 2020 (HealthDay News) -- New data released Tuesday suggests that Pfizer's two-dose coronavirus vaccine begins to work well protecting recipients against COVID-19 within 10 days of the first dose. It also appeared to work well regardless of the trial volunteers' age, sex or weight.Th...