COVID-19 vaccines 90 percent effective, CDC says
The Pfizer and BioNTech and Moderna novel coronavirus (COVID-19) vaccinations are 90 percent effective at reducing infections in fully vaccinated people and 80 percent effective in partially vaccinated people, according to a new report by the U.S. Centers for Disease Control and Prevention (CDC).
Messenger ribonucleuc acid (mRNA) COVID-19 vaccines have been shown to be effective previously in preventing symptomatic SARS-CoV-2 infection in randomized, placebo-controlled clinical trials, the CDC said in a statement. The new study included prospective cohorts of 3,950 healthcare personnel, first responders, and other essential and frontline workers in Arizona, Florida, Minnesota, Oregon, Texas, and Utah who received either the Pfizer and BioNTech or Moderna vaccine from mid-December to mid-March.
Participants completed weekly SARS-CoV-2 testing for 13 consecutive weeks. Two weeks after receiving both recommended doses, their risk of SARS-CoV-2 infection was reduced by 90 percent, according to the study. Additionally, after participants received the first dose, their risk of infection was reduced by 80 percent. Both vaccines prevented both symptomatic and asymptomatic infections, the CDC said.
The findings are the first in the U.S. using real-world conditions to evaluate mRNA vaccine effectiveness of full and partial immunization. The results are in line with research in other countries, including a recent study by The Israel Ministry of Health, which found the Pfizer vaccine to be 97 percent effective in preventing COVID-19, including severe cases and mortality.
In the U.S., more than 53 million people have received a vaccine, as access continues to expand.