A new groundbreaking study in Israel found that over time, the number of SARS-CoV-2 antibodies falls in both previously infected and vaccinated people, but the performance of antibodies improves only after the previous infection and not vaccination.
Led by Dr. Carmit Cohen of Israel’s Sheba Medical Center, the study will be presented at the European Congress of Clinical Microbiology and Infectious Diseases in April. According to the study, researchers found that the number of antibodies present a month after vaccination was higher than in patients who had recovered from COVID-19. However, these numbers declined more steeply in the vaccinated group.
Cohen and her colleagues analyzed antibody-induced immune response in 130 recovered individuals for up to a year and compared it to 402 matched individuals who were double-vaccinated with the Pfizer vaccine but never had COVID-19.
This could explain why double-vaccinated individuals who never contracted COVID-19 are more likely to experience infection after six months.
The study also found that, contrary to expectations, antibodies of recovered patients with a body-mass index of 30 or higher (in the obese range) were higher at all time points when compared with those with a BMI under 30 (overweight to normal weight range). The obese people who had been previously infected were, therefore, better protected against future infection.