Pfizer third dose vaccine, antibody increase: the study

The third dose of Pfizer-BioNTech anti-Covid vaccine is associated, after 10-19 days, with a significant increase in anti-Sars-CoV-2 antibodies in over 60s, without major adverse events. This is the result of an Israeli study, the results of which are published on ‘Jama’ online. The authors evaluated antispike (anti-S) IgG antibody titers before and after the booster in a population such as the senior one that is at high risk of developing severe Covid, and for this reason was the first age group to receive clearance for the third dose. Rabin Medical Center (RMC) offered the recall to workers and their family members and recruited study participants aged 60 and over into the vaccination center. Among the 97 enrolled the average age was 70 years, 61% were women. Before the third dose 97% were HIV positive, meaning they had antibodies. However, the titre level increased significantly after the third dose, from a median of 440 Au / ml to 25,468 Au / ml, and all participants became HIV positive. No significant correlation was observed between age and IgG titers. No variables were significantly associated with higher IgG titers, including gender, days after first vaccination, and comorbidities. A previous study by Israel of 1.1 million adults over 60 vaccinated with two doses and then boostered had already shown that booster was associated with lower rates of confirmed Sars-CoV-2 infections and severe disease. This study adds serological data to clinical data on response to a third dose in adults 60 years of age and older, the authors conclude.