According to a new Sheba Medical Center and Tel Aviv University study, published in the scientific journal Nature Immunology, the effectiveness of a third COVID-19 vaccine dose against PCR-confirmed infection, regardless of symptoms, is 85.6% higher compared to two doses.
In order to analyze the effectiveness of the third vaccine dose, researchers administered the jab to 12,290 healthcare workers who were not previously infected with COVID-19 and had already received the first and second vaccine doses.
Results indicate that out of the the12,290 participants, 407 (3.3%) tested positive for COVID-19 on a PCR test.
Data gathered as part of the study demonstrated that while the increase in antibodies is relatively small at around 170%, a 600% increase in neutralizing antibodies, which bind pathogens and prevent them from spreading infection, was recorded in comparison to the second vaccine dose.
The study also found that the higher levels of antibodies following a third dose of the Pfizer-BioNTech vaccine correlate with a reduced risk of COVID-19 infection.