The Centers of Disease Control and Prevention has released preliminary results of a study involving 4,000 health-care personnel and first responders vaccinated between mid-December 2020 and mid-March 2021. The subjects were drawn from six states and the evaluation was conducted during the first quarter when COVID incidence rates were rising sharply. 

 It was determined that a single dose of either the Pfizer or Moderna vaccine provided 80 percent protection.  Following the second dose, a protection level of 90 percent was attained. Among 2,479 fully vaccinated subjects, three had confirmed infections.  Among 477 receiving one dose, eight cases were diagnosed.  Among the 994 non-vaccinated controls 161 infections were confirmed.

In commenting on the initial data, Dr. Rochelle Walensky Director of the Centers for Disease Control and Prevention, stated “The vaccines receiving FDA Emergency Use Authorization provided early, substantial real-world protection against infection for our nation’s healthcare personnel, first responders, and other frontline essential workers.” Dr. Walensky added, “These findings should offer hope to the millions of Americans receiving coronavirus vaccines each day and to those who will have the opportunity to roll up their sleeves and be vaccinated in the weeks ahead.”

The interim results of the healthcare and first responder study confirm the data submitted by the manufacturers of the two mRNA vaccines following completion of their respective Phase 3 trials in 2020.