Study shoows Pfizer efficacy decreased from 88% to 47% after six months of second dose

World: The U.S. health agencies released data that shows that the effectiveness of the – Pfizer/BioNTech vaccine in preventing infection by the coronavirus decreased from 88 % to 47 % after six months of the second dose.

Lancet medical journal published the data on Monday. The report shows that the vaccine’s effectiveness in preventing hospitalization & death remained high at – 90% for at least 6 months, even against the highly contagious Delta variant of the COVID-19.

As per the study, the decrease in the effectiveness is due to the waning efficacy. The study was performed with the help of electronic health records of around – 3.4 million people who were the members of Kaiser Permanente Southern California between the time period December 2020, to the time when the vaccine first became available – and August of 2021, by Pfizer and Kaiser Permanente researchers.

Senior vice president & the chief medical officer at Pfizer vaccines – Luis Jodar, cited that, “Our variant specific analysis clearly shows that the (Pfizer/BioNTech) vaccine is effective against all current variants of concern, including Delta.”

Vaccine effectiveness against the ‘Delta variant’ was 93% after the first month, declining to 53% after four months. Against other variants of COVID-19, efficacy declined to – 67% from 97%.

The study leader Sara Tart of Kaiser Permanente Southern California’s Department of Research & Evaluation stated that “To us, this suggests Delta is not an ‘escape variant’ that is completely evading vaccine protection.”

Following the statement, Tart added, “If it was, we will probably not have seen high protection after the vaccination because vaccination would not be working in that case. It would start low and stay low.”

The United States Food & Drug Administration has also authorized the use of a booster dose of the Pfizer/BioNTech COVID-19 vaccine for older adults and some Americans at high risk of getting infected.

Scientists have called for more data to study on whether boosters should be recommended for every age group.