SARS-CoV-2 infections among asymptomatic individuals contributed to COVID-19 cases: A cross-sectional study among prospective air travelers from Ghana

Detection of SARS-CoV-2 Variants Imported Through Land Borders at the Height of the COVID-19 Pandemic in Ghana, 2022

Background The World Health Organization recommends surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at points of entry to systematically collect and analyze data to inform decisions about the effective and appropriate use of resources needed for interventions. This study sought to determine the prevalence of SARS-CoV-2 and its variants imported into Ghana by travelers entering the country via land borders from February to July 2022. Methods A cross-sectional approach was employed, where recruited participants consented to the collection of oropharyngeal and nasopharyngeal samples. Specimens were analyzed for the presence of SARS-CoV-2 ribonucleic acid (RNA) using a commercially available VeriQ nCoV-OM COVID-19 Multiplex Detection kit. Amplicon sequencing protocols (ARTIC network, Oxford Nanopore Technologies (ONT), New England Biolabs, British Columbia Centre for Disease Control (BCCDC), COVID-19 Genomics UK (COG-UK), Canadian COVID-19 Genomics Network (CanCOGen), and ONT MinION) were used for SARS-CoV-2 sequencing. Logistic regression and phylogenetic analyses were conducted on the generated data. Results We detected a SARS-CoV-2 prevalence of 3.6% (170/4,621) among a total of 4,621 travelers screened. The average age of travelers was 32.11 ± 11.77, with the majority being male (68%, 3,132/4,621). After adjusting for educational status, household size, vaccination status, and study site, those with primary and tertiary education levels had 1.74 (95% CI: 1.16-2.62, P = 0.007) and 2.27 (95% CI: 1.27-4.05, P = 0.006) higher odds of testing positive for SARS-CoV-2 compared to those with no education. Vaccinated travelers had 0.65 odds (95% CI: 0.48-0.89, P = 0.007) of testing positive for SARS-CoV-2. The Omicron variant (B.1.1.529) emerged as the predominant lineage, constituting 77% (27/35) of isolates, compared to Alpha, Delta, and Recombinant variants. Phylogenetic analysis corroborated this finding, highlighting Delta and Omicron as the dominant circulating SARS-CoV-2 variants. Notably, Ghanaian strains from this study clustered with global variants, suggesting multiple introductions, likely through land borders. Conclusion A low prevalence of SARS-CoV-2 was recorded in this study, prompting the decision to reopen land borders and ease pandemic-related travel restrictions. Omicron was identified as the dominant variant. These findings emphasize the crucial role of routine surveillance at port health and advocate for a collaborative approach to addressing public health crises, preventing unnecessary travel and trade restrictions through data-based decision-making.

Efficient transplacental transfer of SARS-CoV-2 antibodies between naturally exposed mothers and infants in Accra, Ghana

We aimed to determine SARS-CoV-2 antibody seropositivity among pregnant women and the transplacental transfer efficiency of SARS-CoV-2-specific antibodies relative to malaria antibodies among SARS-CoV-2 seropositive mother-cord pairs. This cross-sectional study was conducted in Accra, Ghana, from March to May 2022. Antigen- specific IgG antibodies against SARS-CoV-2 (nucleoprotein and spike-receptor binding domain) and malarial antigens (circumsporozoite protein and merozoite surface protein 3) in maternal and cord plasma were measured by ELISA. Plasma from both vaccinated and unvaccinated pregnant women were tested for neutralizing antibodies using commercial kit. Of the unvaccinated pregnant women tested, 58.12% at antenatal clinics and 55.56% at the delivery wards were seropositive for both SARS-CoV-2 nucleoprotein and RBD antibodies. Anti-SARS-CoV-2 antibodies in cord samples correlated with maternal antibody levels (N antigen rs = 0.7155, p < 0.001; RBD rs = 0.8693, p < 0.001). Transplacental transfer of SARS-CoV-2 nucleoprotein antibodies was comparable to circumsporozoite protein antibodies (p = 0.9999) but both were higher than transfer rates of merozoite surface protein 3 antibodies (p < 0.001). SARS-CoV-2 IgG seropositivity among pregnant women in Accra is high with a boost of SARS-CoV-2 RBD-specific IgG in vaccinated women. Transplacental transfer of anti-SARS-CoV-2 and malarial antibodies was efficient, supporting vaccination of mothers as a strategy to protect infants against SARS-CoV-2.