Despite the effectiveness of the vaccine and high vaccination coverage in Israel, the number of people with severe COVID-19 disease is gradually increasing, and this is probably due to the decrease in immunity provided by vaccines over time.
For this reason, a study was carried out with the participation of medical professionals who measured the titer of IgG and their neutralizing antibodies on a monthly basis. At the same time, various linear models were used to assess the dynamics of changes in the level of antibodies over six months.
Doctors of the Therapeutic Clinic of the Medical School of the Athens National University. The Kapodistrias Theodora Psaltopoulou, Panos Malandrakis, Yannis Danasis and Thanos Dimopoulos (Rector of EKPA) summarize the publication in The New England Journal of Medicine.
New Vaccine Research
The study involved 4868 people, 3808 people participated in the analysis. IgG antibody levels declined at a constant rate, while neutralizing antibodies declined rapidly over three months, after which they reached a relatively stable level.
Six months after taking the second dose, neutralizing antibodies were lower in men than in women (mean 0.64), lower in people over 65 than those aged 18 to 45 (mean 0.58), and in those who had weak immunity (mean value 0.30).
The conclusion says that lower antibody titers after six months were observed in people of the age group 65+ who had some form of immunosuppression (immune problems), and lower antibody titers were observed in men.
For this reason, the FDA approved the introduction of a third, auxiliary dose of vaccine for people over 65 years of age and immunocompromised patients – six months after the second vaccine.