from Silvia Turin
Study on 42 thousand people when there was no Delta variant: drop from 96% to 83.7%. It holds the protection from severe cases which remains at 97%. The data reopen the debate on the third dose which (other research says) again increases the “lost” defenses
The Pfizer vaccine’s effectiveness in preventing infection wanes over time falling, six months after the second dose, from 96% to 83.7%. The valence against severe forms of Covid disease, on the other hand, remains high at 97%.
The results of a study published online without a review yet say so. The efficacy against symptomatic Covid is decreased by about 6% every two myes, falling to 83.7% after six months. The results come from 42,000 volunteers from six countries who participated in a clinical trial started by Pfizer and BioNTech last July and ended on March 13. In the period from one week to two months after the second dose, the effectiveness was 96.2 percent. In the two to four month period, effectiveness dropped to 90.1 percent. And from four months to six months, the effectiveness reached 83.7 percent. The study did not measure the rate of asymptomatic viral infections.
Same finding from Israel
The data comes from a period in which the Delta variant, which makes vaccines somewhat less effective against infections, it was not dominant as it has now become in hundreds of countries around the world, although recent studies have shown that vaccines remain highly protective against the worst outcomes of Covid even with infections caused by the Delta. The new study comes in the wake of asimilar analysis from Israel that suggested Pfizer vaccine protection may be on the decline in the country with Pfizer vaccination record. The data released in May by the Israeli ministry of health showed an efficacy of the Pfizer vaccine equal to 94.3% in the prevention of asymptomatic infections, while in June, when the Delta variant was more widespread, the coverage was around to 64%. Compared to severe disease, the efficacy rate was only 5% down.
Pfizer also shares the results on the third dose
With coronavirus cases on the rise in many states, the findings could sway government decisions on the provision of the third dose and pharmaceutical companies have a vested interest in promoting targeted studies. Right now Pfizer itself shared the results of the experiments on the third dose of its original vaccine against the Delta variant: the antibody levels are increased by 5 times between 18-55 years e of 11 times between 65-85 years.
Decisions on the third dose
The decision on the third dose, however, is not unanimous and there is great uncertainty: slow down for now Food and Drug Administration Usa who stated that “fully vaccinated Americans do not need a booster dose right now,” stressing that it is not up to individual companies to decide if and when the booster will be needed. Even the European Medicines Agency (EMA) said: “It is too early to confirm if and when a booster dose will be needed for Covid-19 vaccines, because there is not enough data from immunization campaigns and studies yet. course to understand how long the protection from vaccines will last ». However, some countries have taken action: Turkey has already started offering a third dose of Sinovac (or Pfizer) to some people. Indonesia and Thailand have agreed to give the third dose of Moderna and Pfizer to some people vaccinated with CoronaVac. Many are considering the third dose for the elderly and the immunosuppressed.
July 28, 2021 (change July 29, 2021 | 09:00)