Knowing the Antibody Status may influence compliance of health care workers to COVID-19 booster dose

Abstract Background Previous studies showed that the fourth SARS-CoV-2 vaccine dose has a protective effect against infection, as well as against severe disease and death. This study aimed to examine whether knowledge of a high level antibody after the 3rd dose may reduce compliance to the 4th booster dose among health care workers. Methods We conducted a prospective cohort study among health care workers vaccinated with the first three doses at Rambam Healthcare Campus, a tertiary hospital in northern Israel. Participants underwent a serological test before the 4th booster vaccine was offered to all of them, with results provided to participants. The population was divided into two groups: those with antibody below 955 AU/ml, and those with 955 AU/ml and higher, a cutoff found protective in a previous study. Multiple logistic regression was carried out to compare the compliance to the 4th booster between the two groups, adjusted for demographic and clinical variables. Results After adjusting for the confounding variables, the compliance was higher in those with antibody levels below 955 AU/ml (OR = 1.41, P = 0.05, 95% CI 1.10-1.96). In addition, male sex, and age of 60 years and above were also associated with higher vaccination rate (OR = 2.28, P < 0.001, 95% CI 1.64 - 3.17), (OR = 1.14, P = 0.043, 95% CI 1.06 - 1.75), respectively. Conclusions Knowledge of the antibody status may affect compliance with the booster dose. Considering waning immunity over time, reduced compliance may affect the protection of health care workers who declined the 4th dose. Key messages • Knowing the antibody status may affect compliance of health care workers with the booster dose. • Reduced compliance of health care workers may affect their protection.