Abstract
The objectives of this study were to assess the dynamics of the SARS-CoV-2 anti-RBD-IgG response over time among older people after COVID-19 infection or vaccination and its comparison with indicative levels of protection. Geriatric patients with SARS-CoV-2 serological test results were included and divided into three groups. A vaccine group (n = 34), a group of natural COVID-19 infection (n = 32), and a group who contracted COVID-19 less than 15 days after the first injection (n = 17). Eighty-three patients were included; the median age with IQR was 87 (81-91) years. In the vaccine group at 1 month since the first vaccination, the median titer of anti-RBD-IgG was 620 (217-1874) BAU/ml with 87% of patients above the theoretical protective threshold of 141 BAU/ml according to Dimeglio et al. (J Infec. 84(2):248-88, [7]). Seven months after the first vaccination, this titer decreased to 30 (19-58) BAU/ml with 9.5% of patients > 141 BAU/ml. In the natural COVID-19 infection group, at 1 month since the date of first symptom onset, the median titer was 798 (325-1320) BAU/ml with 86.7% of patients > 141 BAU/ml and fell to 88 (37-385) with 42.9% of patients > 141 BAU/ml at 2 months. The natural infection group was vaccinated 3 months after the infection. Five months after the vaccination cycle, the median titer was 2048 (471-4386) BAU/ml with 83.3% of patients > 141 BAU/ml. This supports the clinical results describing the decrease in vaccine protection over time and suggests that vaccination after infection can maintain significantly higher antibody titer levels for a prolonged period of time.
Keywords: Anti-RBD IgG; Dynamics; Kinetics; SARS-CoV-2; Serology.
【저자키워드】 SARS-CoV-2, serology, Dynamics, Kinetics, Anti-RBD IgG, 【초록키워드】 COVID-19, serological test, Vaccine, vaccination, Infection, COVID-19 infection, Patient, Antibody titer, age, threshold, natural infection, Protective, Support, symptom onset, Older, three groups, injection, first vaccination, decrease, vaccine group, less, maintain, significantly higher, the vaccine, IQR, patients with SARS-CoV-2, the median, the SARS-CoV-2, 【제목키워드】 Evolution, BNT162b2 vaccine, immune response, COVID-19 infection, threshold, Protective, Older,