Seroprevalence of SARS-CoV-2 neutralizing antibodies among travelers entering Ghana through major land borders, pre- and post-opening of borders, 2022

Abstract

Sero-epidemiological surveillance of SARS-CoV-2 in Africa has been pivotal in informing evidence-based pandemic response and border control strategies. To mitigate viral transmission, Ghana initially closed its air and land borders but later reopened them under regulated conditions. This study evaluated the seroprevalence of SARS-CoV-2 neutralizing antibodies among travelers entering Ghana via major land borders pre- and post-opening. Using a cross-sectional study design, individuals aged 18 years and above who entered Ghana through ten major land borders from February to July 2022 were recruited consecutively after providing informed consent. During enrolment, participants completed a semi-structured questionnaire to gather data on background characteristics, vaccination status, travel history, and symptoms. Blood samples were collected and analyzed using the WANTAI ELISA to detect SARS-CoV-2 neutralizing antibodies. The overall seroprevalence of SARS-CoV-2 neutralizing antibodies was 92.3% (95% CI: 91.4–93.0%). Seroprevalence was significantly higher before border reopening 95.7% (95% CI: 94.2–97.1%) compared to post-reopening levels 91.6% (95% CI: 91.0–92.5%). Travelers from specific entry points, Oseikojokrom, Akanu, Saboba, and Tatale, had significantly lower odds of seropositivity compared to those from Aflao (p < 0.05). Vaccinated travelers had 2.5 times higher odds of seropositivity (aOR: 2.5, 95% CI: 1.7–3.5) before reopening and 1.8 times higher odds (aOR: 1.8, 95% CI: 1.3–2.6) after reopening. The persistently high seroprevalence of SARS-CoV-2 neutralizing antibodies pre- and post-border reopening suggests that Ghana posed little to no risk of cross-border transmission. The study’s findings informed the decision to reopen Ghana’s land borders and emphasized the importance of strong border surveillance to prevent the importation and spread of pathogens.