A new Sheba study involving first-generation Pfizer COVID-19 vaccines, published in the New England Journal of Medicine, showed that the fourth vaccine dose increased antibody levels for only around 13 weeks.
Conducted by Sheba researchers alongside experts from the Israeli Health Ministry and Columbia University researchers, the study comprised over 6,000 Sheba employees and volunteers.
Based on the findings, Sheba researchers suggest healthcare providers should plan booster shot administration carefully, as added protection against infection peaks for a relatively short period, i.e., boosters should be given when episodes of high infection are expected or when specific patients face circumstances that make them more prone to infection and serious disease.
According to Prof. Regev-Yochay, Director of the Infectious Prevention and Control Unit at Sheba and one of the study’s lead authors, it is necessary to “take into consideration not only surges in infection, but also personal medical conditions, upcoming events, travel plans, and high risk periods.”
While it remains unclear how antibody levels correlate with protection against serious illness, the study did not examine the possibility that the vaccine may offer protection against severe forms of the disease for longer than three months, the period in which antibody levels are high.
