According to a study by Centers for Disease Control and Prevention, Pfizer (NYSE: PFE) and Moderna’s (NASDAQ: MRNA) vaccines were 90% effective after two doses, and 80% effective after only one dose.
After analyzing 4,000 participants, the study showed that effectiveness of partial immunization was visible two weeks after the initial dose. None of the participants had a previous laboratory record of Covid-19 infection.
Nevertheless, federal health officials insist two doses are necessary as its effectiveness was increased by the second dose.
“These findings indicate that authorized mRNA COVID-19 vaccines are effective for preventing SARS-CoV-2 infection, regardless of symptom status, among working-age adults in real-world conditions,” the U.S. agency wrote in the study. “COVID-19 vaccination is recommended for all eligible persons.”
The study is the first evaluation made by the government on the shots effectiveness, aside from the drugmakers first outcome. Results have a possibility of changing when vaccines are dispersed throughout larger populations, therefore participants provided with nasal swab test kits to use on a weekly basis.
“The evidence base for (currently available) COVID-19 vaccines is already strong, and continues to mount ever higher with studies like this one,” said David Holtgrave, dean of the University at Albany’s School of Public Health, in an email.
The new information may cause arguments from health experts and public health officials that believe Americans should be given only one dose in order to advance the rate of vaccinations within the country. Furthermore, the CDC report was published just minutes before the agency’s director, Dr. Rochelle Walensky, said the U.S. is facing “impending doom” as Covid-19 cases rise.
“The reason that they are two-dose vaccines is that the second doses give you a titer of neutralizing antibodies, virus-specific neutralizing antibodies that is almost 10 growth fold greater than after the first dose,” said Dr. Paul Offit, a voting member of the FDA’s Vaccines and Related Biological Products Advisory Committee.