Study: COVID-19 Vaccine Antibodies Last Only 6 Months, Boosters Necessary

VERONA: In a recent study, researchers have discovered that it only takes six months for the number of antibodies produced by the Pfizer-BioNTech COVID-19 vaccine to decrease drastically, and the number of antibodies produced is subsequently affected by an individual’s sex and age.

Safe and effective vaccines are among the best responses we have had against the COVID-19 pandemic, which took the world by storm in early 2020, with many vaccines being touted as 90% efficient against the novel virus. However, experts are aware that the immunity developed through these tends to reduce over time.

The researchers of this study observed collected data from 787 healthcare workers in Verona, Italy.

The healthcare workers, aged between 21 to 75 years, had been administered two doses of the Pfizer-BioNTech vaccine. The data comprised the SARS-CoV-2 antibody amount levels before their first vaccination and after their second vaccination, as well as the amounts after 1, 3, and 6 months post-second vaccination.

The researchers learned that antibody levels reduced by more than 50% within six months of the second vaccination and that there were differences in the total antibody levels amongst participants, based on their age and sex.

They also discovered that individuals under 65 years had more than double the antibody count compared to those over 65 years or older. This followed a linear pattern as the age went down. Additionally, men had a lower antibody count compared to women.

“Our study establishes that booster shots for all adults will be imperative to keep antibody levels up and produce an effective immune response against COVID-19, preventing mortalities,” said Dr Brandon Michael Henry, co-leader of the study and postdoctoral researcher at the Texas Biomedical Research Institute.

“Vaccines are considered an ‘artificial’ form of infection. Therefore, antibody decline is similar in both vaccine recipients and people recovering from a COVID-19 infection.” said Prof. Giuseppe Lippi, professor of clinical biochemistry at the University of Verona and fellow co-author, while agreeing that booster shots will be vital in the future.

“Antibody decay is linked to sex and age. Hence booster doses of vaccines would be required for everybody,” he confirmed.

The Journal of Medical Biochemistry has accepted this study for publishing, but it is also available as a preprint.