Response of antibody titers to SARS-CoV-2 vaccination and clinical outcomes during the predominance of the Omicron variant in Colombia

Introduction: The response to vaccination against the virus that causes severe acute respiratory infection syndrome coronavirus 2 is lower in renal transplant recipients than in the general population. The data obtained from Latin America showed reduced immunogenicity under inactivated virus vaccination schedules and messenger ribonucleic acid platforms. Methods: A retrospective cohort study including renal transplant recipients from Colombia with a two-dose vaccination schedule against severe acute respiratory infection syndrome coronavirus 2 with Pfizer, AstraZeneca, Moderna, Jansen, and Sinovac vaccines between March 1, 2021 and December 1, 2021, was carried out with a follow-up period to evaluate outcomes until May 2022. The outcomes correspond to the titers of immunoglobulin G antibodies against the receptor binding domain of the severe acute respiratory infection syndrome coronavirus 2 spike and a composite outcome of mortality, general, and intensive care unit hospitalization. Results: In total, 215 renal transplant recipients with two doses of vaccination for severe acute respiratory infection syndrome coronavirus 2 during the predominance of the Omicron variant in Colombia were included, with the measurement of immunoglobulin G antibody titers against the receptor binding domain of the severe acute respiratory infection syndrome coronavirus 2 spike at 8 weeks of vaccination. The mean age was 52.1 years, and the standard deviation was ± 14.2; severe acute respiratory infection syndrome coronavirus 2 infection occurred in 20% of the population, of which 23.26% required hospitalization, 13.95% were under intensive care unit management, and four cases of mortality (9.3%) were reported. Of the total population, 52.5% had antibody titers higher than 0.8 IU/mL (median 0.77 IU/mL, interquartile range 0.4–131). Patients with severe acute respiratory infection syndrome coronavirus 2 infection had a median antibody titer of 0.4 IU/mL (interquartile range 0.4–3.45), and those without infection had a median antibody titer of 1.8 IU/mL (interquartile range 0.4–202) ( p  = 0.015). Conclusion: Anti-severe acute respiratory infection syndrome coronavirus 2 antibody titers with a cutoff point less than 0.8 IU/mL are associated with increased risk of severe acute respiratory infection syndrome coronavirus 2 infection.