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

Abstract

Background: HIV 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.

Methods: We conducted a nested study of 62 HIV-uninfected and 64 healthy women living with HIV, as well as their HIV-exposed uninfected (N = 61) and HIV-unexposed (N = 64) infants, participating in a prospective cohort. SARS-CoV-2 serology was performed on plasma collected between May 1, 2020-February 1, 2022 to determine the incidence, risk factors, and symptoms of infection. SARS-CoV-2 RNA PCR and sequencing was also performed on available stool samples from seropositive participants.

Results: SARS-CoV-2 seropositivity was found in 66% of the 126 mothers and in 44% of the 125 infants. There was no significant association between SARS-CoV-2 infection and maternal HIV (Hazard Ratio [HR] = 0.810, 95% CI: 0.517-1.27) or infant HIV exposure (HR = 1.47, 95% CI: 0.859-2.53). Maternal SARS-CoV-2 was associated with a two-fold increased risk of infant infection (HR = 2.31, 95% CI: 1.08-4.94). Few participants (13% mothers, 33% infants) had symptoms; no participant experienced severe COVID-19 or death. Seroreversion occurred in about half of mothers and infants. SARS-CoV-2 sequences obtained from stool were related to contemporaneously circulating variants.

Conclusions: These data indicate that postpartum Kenyan women and their infants were at high risk for SARS-CoV-2 infection and that antibody responses waned over an average of 8-10 months. However, most cases were asymptomatic and healthy women living with HIV did not have a substantially increased risk of infection or severe COVID-19.

Fig 1. SARS-CoV-2 acquisition from May 1, 2020-February 1, 2022 in postpartum Kenyan women and their infants.

Kaplan-Meier hazard functions for participants’ estimated date of infection are shown for (A) all mothers and (B) all infants, (C) mothers stratified by HIV status, (D) infants stratified by HIV exposure, (E) infants stratified by maternal SARS-CoV-2 infection, and (F) infants stratified by maternal HIV and SARS-CoV-2 infection. HEU = HIV-exposed uninfected, HUU = HIV-unexposed uninfected. All women enter the at-risk period on May 1, 2020; infants enter the risk period either at May 1 or on their date of birth, if after May 1. Timing of SARS-CoV-2 infection is estimated as the midpoint between the last negative and the first positive antibody test; for participants whose last negative antibody test was prior to May 1, timing of infection is estimated as the midpoint between May 1 and the first positive test. In (E) and (F), infants’ time at risk is censored on November 1, 2021 since no infants with a SARS-CoV-2 negative mother remained in follow-up for comparison.

Fig 2. Detection of SARS-CoV-2 antibody among mothers and infants over time.

(A) SARS-CoV-2 antibody levels over time relative to the first seropositive time point (0 months). Individual patterns in infants (top) and mothers (bottom) are shown in grey. Grouped by maternal HIV status, running means are shown for HIV-uninfected women or HIV-unexposed infants in black and women living with HIV or HIV-exposed infants in red. Limit of detection denoted by dashed vertical line. (B) and (C) are Kaplan-Meier hazard functions for participants’ estimated time to loss of detectable antibodies stratified by maternal HIV status and infant HIV exposure, respectively. HEU = HIV-exposed uninfected, HUU = HIV-unexposed uninfected. The risk period for loss of detectable antibody begins at the participant’s first positive serology test and ends either at the time of loss of detectable antibodies (estimated as the midpoint between the last positive test and first negative test after a positive test) or at the time of the most recent positive test.

Fig 3. SARS-CoV-2 serology and stool viral RNA results over calendar time.

Results of SARS-CoV-2 serology and quantitative real-time PCR testing of stool samples from Linda Kizazi participants that first tested seropositive and had ≥1 available stool sample collected between May 1-December 31, 2020. Anonymized ID numbers on y-axis for mothers (M) and infants (B). Grey circles indicate date of last seronegative serology test and orange circles indicate date of first seropositive sample. White triangles represent SARS-CoV-2 RNA-negative and red triangles represent RNA-positive stool samples. Calendar time is on the x-axis.