However, it is highly effective if people have both doses. The study took place between december 2020 and august 2021.
As with any vaccine, the pfizer vaccine (comirnaty) may not fully protect everyone who gets it.
How effective is the covid vaccine. The trial found the vaccine to be 90% effective overall, and 100% effective against moderate and severe disease. Yesterday in the new england journal of medicine, two more studies confirmed high rates of vaccine effectiveness (ve), even against severe disease, and the vaccines' potential to prevent disease transmission. Both studies were published as letters today.
Johns hopkins medicine considers them to. According to researchers in turkey, the vaccine is 91.25% protective, while scientists in indonesia have said that it’s 65.3% effective, and the butantan institute in são paulo, brazil recently. Get details on how the vaccines work.
Cdc continuously monitors how well the vaccines are working. The testing methods for the vaccines are not all alike, which makes it difficult to compare them. The rapid development and urgency of producing a vaccine for the covid‑19 pandemic was expected to increase the risks and failure rate of delivering a safe, effective vaccine.
   additionally, research at universities is obstructed by physical distancing and closing of laboratories. Number of shots and intervals between doses. The ceo of one vaccine maker said immunity may start to fade within a year.