Study: COVID Protection Weakens Gradually after Second Dose of the Pfizer Vaccine

A study published in the British Medical Journal found a gradual increase in the risk of COVID-19 on the 19th day after taking a second dose of the Pfizer / Biontech vaccine against the new coronavirus, Medical Express reported.

The study was conducted by the Leumit Health Research Institute in Israel. The country was one of the first in the world to launch a mass vaccination campaign against COVID-19 in December 2020. Since June this year, the country has seen a new increase in infections, the newspaper writes.

The results confirm that the Pfizer / Biontech vaccine provides excellent protection in the first weeks after vaccination, but shows that it weakens in some people over time.

Determining the time after vaccination and the risks of infection provide important information about the need for a third dose and the most appropriate time for this.

Therefore, the researchers analyzed the electronic health records of 80,057 people with an average age of 44 who underwent a PCR test at least three weeks after the second dose of vaccine and did not report a previous infection.

Of all participants in the study, 7973 people (9.6 percent) gave a positive test result. The percentage of positive results increases with increasing time elapsed since the second dose. In all age groups, 1.3 percent of the participants tested positive for the new coronavirus 21-89 days after the second dose, 2.4 percent after 90-119 days, 4.6% after 120-149 days, 10.3% after 150 -179 days and 15.5% after 180 or more days


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