Preliminary findings from Israel found people who received a fourth shot of Pfizer-BioNTech's COVID-19 vaccine had a fivefold increase in antibodies a week later, The Wall Street Journal reported Jan. 4.
Israeli Prime Minister Naftali Bennett announced the findings during a Jan. 4 news conference, saying the early results "demonstrate a much higher level of protection than without the fourth dose, both in relation to infection and the spread of the virus and in relation to severe morbidity.”
The findings were released after Israel became the first country to broadly roll out fourth doses for healthcare workers and people 60 and older Jan. 2.
Researchers from Israel's Sheba Medical Center led the study, which involved 150 medical workers who had all previously received the Pfizer vaccine. The initial analysis screened for adverse reactions to the fourth shot, and found side effects were similar to those after the initial doses.
A secondary analysis looked at antibody levels one week after the second boosters were administered. The early findings indicate the shot led to a fivefold jump in antibodies. Sheba Medical Center is also planning a similar trial in which participants who've received three doses of Pfizer's vaccine will receive an extra dose of Moderna's shot.
To read the full Wall Street Journal article, click here.