HIV and SARS-CoV-2 infection in postpartum Kenyan women and their infants

BackgroundHIV may increase SARS-CoV-2 infection risk and COVID-19 severity generally, but data are limited about its impact on postpartum women and their infants. As such, we characterized SARS-CoV-2 infection among mother-infant pairs in Nairobi, Kenya. MethodsWe conducted a nested study of 53 HIV-uninfected and 51 healthy women living with HIV, as well as their HIV-exposed uninfected (N=41) and HIV-unexposed (N=48) infants, participating in a prospective cohort. SARS-CoV-2 serology was performed on plasma collected between 1 May-31 December 2020 to determine the incidence, risk factors, and symptoms of infection. SARS-CoV-2 RNA PCR and sequencing was also performed on stool samples from seropositive participants. ResultsSARS-CoV-2 seropositivity was found in 38% of the 104 mothers and in 17% of the 89 infants. There was no significant association between SARS-CoV-2 infection and maternal HIV (Hazard Ratio [HR]=1.51, 95% CI: 0.780-2.94) or infant HIV exposure (HR=1.48, 95% CI: 0.537-4.09). Maternal SARS-CoV-2 was associated with a >10-fold increased risk of infant infection (HR=10.3, 95% CI: 2.89-36.8). Twenty percent of participants had symptoms, but no participant experienced severe COVID-19 or death. Seroreversion occurred in [~]30% of mothers and infants. SARS-CoV-2 sequences obtained from stool were related to contemporaneously circulating variants. ConclusionsThese data indicate that postpartum Kenyan women and their infants were at high risk for SARS-CoV-2 infection in 2020, and that antibody responses waned rapidly. However, most cases were asymptomatic and healthy women living with HIV did not have a substantially increased risk of infection or severe COVID-19.

SARS-CoV-2 antibody binding and neutralization in dried blood spot eluates and paired plasma

Widescale assessment of SARS-CoV-2-specific antibodies is critical to understanding population seroprevalence, correlates of protection, and the longevity of vaccine-elicited responses. Most SARS-CoV-2 studies characterize antibody responses in plasma/sera. While reliable and broadly used, these samples pose several logistical restrictions such as requiring venipuncture for collection and cold chain for transportation and storage. Dried blood spots (DBS) overcome these barriers as they can be self-collected by fingerstick and mailed and stored at ambient temperature. Here, we evaluate the suitability of DBS for SARS-CoV-2 antibody assays by comparing several antibody responses between paired plasma and DBS from SARS-CoV-2 convalescent and vaccinated individuals. We found that DBS not only reflected plasma antibody binding by ELISA and epitope profiles using phage-display, but also yielded SARS-CoV-2 neutralization titers that highly correlated with paired plasma. Neutralization measurement was further streamlined by adapting assays to a high-throughput 384-well format. This study supports the adoption of DBS for numerous SARS-CoV-2 binding and neutralization assays.