Work

Dynamics of anti-SARS-CoV-2 antibodies in the Albanian population: Impact of infection- and vaccine-induced immunity during the COVID-19 pandemic

Year: 2024

Type: article

Abstract: • This study examined SARS-CoV-2 antibody responses in Albanians from Aug 2021 to Aug 2022. • By August 2022, one vaccine dose equaled antibody levels of two doses in younger individuals. • Older individuals (aged ≥61 years) needed two doses for comparable antibody responses. • Hybrid immunity means that one dose may suffice for those with previous COVID-19 infection. • The results suggest refining COVID-19 vaccination strategies in middle-income countries. Understanding immune response dynamics during the COVID-19 pandemic is crucial for optimizing future vaccine strategies. This study investigated the infection- and vaccine-induced SARS-CoV-2 antibody responses in the Albanian population from August 2021 to August 2022. This used a cross-sectional approach, analyzing two independent, randomly selected population samples over 1 year. Participants’ demographic, health, vaccination, and COVID-19 data were collected, with blood samples assessed via enzyme linked immunosorbent assay for immunoglobulin G class anti-spike and anti-nucleocapsid antibodies. By August 2022, all individuals receiving one vaccine dose achieved antibody levels comparable to those receiving two doses (median 7.71 index ratio [IR] vs 7.00 IR). In August 2021, those with previous COVID-19 infection receiving one vaccine dose showed median anti-spike immunoglobulin G levels of 7.22 IR compared with 4.84 IR in those without previous infection receiving two doses. However, individuals aged ≥61 years required two vaccine doses to achieve similar immune responses as younger individuals with one dose. These findings underscore the importance of hybrid immunity, suggesting one vaccine dose may suffice for individuals with previous COVID-19 infection, whereas older adults require additional doses for optimal protection. This study provides insights into humoral immune response dynamics, which is crucial for refining COVID-19 vaccination strategies in middle-income countries with low vaccination coverage and high infection rates.

Source: IJID Regions

DOI: 10.1016/j.ijregi.2024.100440