New revelations are coming about the coronavirus vaccine from Pfizer as shown by effectiveness is reduced by up to 50%.
Vertical decline in the effectiveness of the Pfizer vaccine, five months after second dose in preventing a new infection (of any variant) shows new major American scientific research.
On the contrary, the effectiveness of the vaccine remains very high at about 90% against hospitalization and death. At least for six months even against the highly contagious Delta variant of the coronavirus.
Researchers at Pfizer and the medical center Kaiser Permanente of Southern California, which made the relevant publication in the medical journal The Lancet, analyzed data on approximately 3,4 million people with a mean age of 45 years during the period December 2020-August 2021. Of these, 5,4% had been diagnosed with coronavirus and 6,6% of them had needed hospitalization.
Pfizer: The reduction in efficiency is noticeable
The study found that for them fully vaccinated in the first half the efficacy against the probability of infection was 73% and against hospitalization 90%. Efficacy against the risk of hospitalization due to Delta strain infection, regardless of age, remained at 93% for up to six months.
However, the efficacy against the possibility of infection decreased from 88% in the first month after full vaccination to 47% after five months. In particular, compared to Delta, the efficacy against the probability of infection was 93% in the first month after the second dose, but decreased to 53% after four months. Against other coronavirus strains the efficacy was 97% in the first month after full vaccination, but dropped to 67% after four to five months.
The study estimates that the decrease is probably due to impaired efficiency vaccine over time, despite the fact that Delta is evading immune protection, a conclusion which is probably in favor of a third booster dose after a few months.
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