AstraZeneca’s COVID-19 vaccine 79 percent effective against symptomatic COVID-19 in U.S. study

As the debate over AstraZeneca’s AZD1222 COVID-19 vaccine rages in Europe, the results of a phase three trial in the United States have shown the vaccine to be 79 percent effective at preventing symptomatic COVID-19 and 100 percent effective at preventing severe cases and hospitalization.

The announcement marked the primary efficacy endpoint for the trial and was paired with the news that efficacy held at 80 percent for those most vulnerable — those aged 65 years and older. Results stemmed from 32,449 participants, during which 141 people came down with COVID-19. At least 21,583 participants received the vaccine, while the rest received a placebo. The vaccine was also well-tolerated, with no safety concerns emerging during testing.

The trial consisted of two doses administered over a four-week period.

“These findings reconfirm previous results observed in AZD1222 trials across all adult populations, but it’s exciting to see similar efficacy results in people over 65 for the first time,” Ann Falsey, professor of Medicine at University of Rochester School of Medicine and co-lead Principal Investigator for the trial, said. “This analysis validates the AstraZeneca COVID-19 vaccine as a much-needed additional vaccination option, offering confidence that adults of all ages can benefit from protection against the virus.”

While this is just an interim analysis, the primary analysis will be submitted to the U.S. Food and Drug Administration as AstraZeneca pursues Emergency Use Authorization. That analysis will be submitted for publication in a peer-reviewed journal at the same time.

If authorized, the vaccine would provide another type of protection capable of being stored and transported under normal refrigerated conditions. It could go for at least six months at those temperatures, without the need for deep freeze, unlike several other COVID-19 vaccines.