Assessment of SARS-CoV-2 neutralizing antibody persistence using LFIC: a prevalence study after booster doses.

BACKGROUND: The primary immunization against SARS-CoV-2 has yielded protection rates of up to 95%. The evolution of the original strain of SARS-CoV-2 towards emerging variants which have higher transmissibility, severity of disease and greater viral escape, have promoted the necessity of vaccine booster doses. The third dose of the vaccine provides protection, but its long-term durability remains uncertain. Our aim was to know the vaccine coverage at the University of Alicante (UA) after one year of administration of vaccine booster doses through the detection of anti-SARS-CoV-2 antibodies with a rapid serological test. METHODS: A cross-sectional study was carried out on the prevalence of antibodies against Spike protein of SARS-CoV-2 using a serological test based on lateral flow immunochromatography. We applied a logistic regression to the available variables by the statistics program SPSS 29.0. RESULTS: 565 subjects were tested, 70.1% were women and the average age was 48.2 years old. 93.5% of the tests performed indicated the presence of Spike-protein antibodies against SARS-CoV-2. The time since the last exposure to the viral antigens, whether via vaccination or via infection, revealed an increase in the odds of returning a negative result for antibodies against SARS-CoV-2. CONCLUSIONS: Our results reinforce the temporary nature of the protection of anti-SARS-CoV-2 antibodies and the need for booster doses, supporting the continuity of vaccinations.