The study, published in the New England Journal of Medicine, provides evidence that the vaccine, mRNA-1273, can prevent symptomatic infection.
The results are similar to those of the first interim analysis of the study announced by Moderna in November which showed a vaccine efficacy of 94.5%.
The new article published on Wednesday said that among the more than 30,000 participants randomized to receive the vaccine or a placebo, 11 of those in the vaccinated group developed symptomatic Covid-19 compared to 185 participants who received the placebo, demonstrating an efficacy of 94, 1% in preventing symptomatic COVID-19.
Severe cases of Covid-19 only occurred in participants who received the placebo.
“Our work continues. In the coming months we will have more and more data to better define how this vaccine works, but the results so far show an efficacy of 94.1%. These figures are convincing.” said Lindsey Baden, an infectious disease research company. specialist at Brigham and Women’s Hospital in the United States.
“And, most importantly, the data suggests protection against serious illness, indicating that the vaccine could have an impact in preventing hospitalizations and deaths, at least in the first months after vaccination.”
The study recruited 30,420 adult participants at 99 US sites, including more than 600 participants enrolled in Brigham.
Eligible participants were 18 years of age or older, with no known history of SARS-CoV-2 infection and whose location or circumstances placed them at appreciable risk of infection with SARS-CoV-2 and / or at a high risk of severe Covid-19.
Participants received their first injection between July 27 and October 23, 2020, followed by a second injection 28 days later.
In the placebo group, 185 participants developed symptomatic disease of Covid-19; in the vaccine group, 11 participants did so.
Thirty participants had severe Covid-19 – all in the placebo group, the study said.
Overall, reactions to the vaccine were mild – around half of the recipients suffered fatigue, muscle aches, joint pain and headaches, more so after the second dose, he added.
“While these results are encouraging, they are limited by the short duration of follow-up so far. Longer-term data from the ongoing study may allow us to more carefully assess vaccine efficacy in different groups, determine the impact on asymptomatic infection, understand when immunity wanes, and determine whether vaccines affect infectivity, ”Baden said.
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