Passive and active immunity in infants born to mothers with SARS-CoV-2 infection during pregnancy: Prospective cohort study

SARS-CoV-2 seropositivity in African women living with HIV and their infants

BACKGROUND

SARS-CoV-2 seropositivity data in women living with HIV (WLHIV), their infants and associated factors in this subpopulation remain limited. We retrospectively measured SARS-CoV-2 seropositivity from 07/2020-11/2021 among WLHIV and their children in the PROMOTE observational cohort in Uganda, Malawi, and Zimbabwe prior to widespread SARS-CoV-2 vaccination in those countries.

METHODS

Plasma stored during 3 waves of the COVID-19 pandemic in East/Southern Africa were tested for SARS-CoV-2 specific IgG antibodies (Ab) using serological assays that detect adaptive immune responses to SARS-CoV-2 spike protein. (EUROIMMUN, Mountain Lakes, New Jersey and Roche Diagnostics, Indianapolis, IN). Modified-Poisson regression models were used to calculate prevalence rate ratios (PRR) and 95% confidence intervals (CI) to identify sociodemographic and clinical risk factors.

RESULTS

PROMOTE samples from 918 mothers and 1237 children were analysed. Overall, maternal SARS-CoV-2 seropositivity was 60.1% (95% CI: 56.9 -63.3) and 41.5% (95%CI: 38.8 - 44.2) for children. Non-breastfeeding mothers had a 31% higher risk of SARS-CoV-2 seropositivity compared to breastfeeding mothers (aPRR=1.31, 95%CI: 1.08-1.59). WLHIV with undetectable viral load had a 10% increased risk of SARS-CoV-2 seropositivity (aPRR=1.10, 95%CI: 0.89-1.37). Moreover, those who were normotensive had 12% increased risk SARS-CoV-2 seropositivity (aPRR= 1.12, 95% CI: 0.68-1.85) compared to women with hypertension. Children between 2 and 5 years had a 19% reduced risk of SARS-CoV-2 seropositivity (aPRR=0.81, 95%CI: 0.64-1.02) when compared to younger children. Mother/infant SARS-CoV-2 serostatuses were discordant in 346/802 (43.1%) families tested: mothers+/children- in 72.3%; mothers-/children+ in 26.3%; child+/sibling+ concordance was 34.6%.

CONCLUSIONS

These SARS-CoV-2 seropositivity data indicate that by late 2021, about 60% of mothers and about 40% of children in a cohort of HIV-affected families in eastern/southern Africa had been infected with SARS-CoV-2. More mothers than their infants tested SARS-CoV-2+, likely due to a greater external exposure for mothers linked to daily routines/employment, and school closures. Breastfeeding was protective for mothers, likely because of higher likelihood of staying home with young children, and thus less exposure. Discordant results between children within the same families underscores the need to further understand transmission dynamics within households.

Serologic evolution and follow-up to IgG antibodies of infants born to mothers with gestational COVID

BACKGROUND

It is known that SARS-CoV-2 antibodies from pregnant women with SARS-CoV-2 infection during pregnancy cross the placenta but the duration and the protective effect of these antibodies in infants is scarce.

METHODS

This prospective study included mothers with SARS-COV-2 infection during pregnancy and their infants from April 2020 to March 2021. IgG antibodies to SARS-CoV-2 spike protein were performed on women and infants at birth and at two and six months during follow-up. Anthropometrical measures and physical and neurological examinations and a clinical history of symptoms and COVID-19 diagnosis were collected. Simple linear regression was performed to compare categorical and continuous variables. To compare the mother's and infant's antibody titers evolution, a mixed linear regression model was used. A predictive model of newborn antibody titers at birth has been established by means of simple stepwise linear regression.

RESULTS

51 mother-infant couples were included. 45 (90%) of the mothers and 44 (86.3%) of the newborns had a positive serology al birth. These antibodies were progressively decreasing and were positive in 34 (66.7%) and 7 (13.7%) of infants at 2 and 6 months, respectively. IgG titers of newborns at birth were related to mothers' titers, with a positive moderate correlation (Pearson's correlation coefficient: 0.82, p < 0,001). Fetal/maternal antibodies placental transference rate was 1.3 (IQR: 0.7-2.2). The maternal IgG titers at delivery and the type of maternal infection (acute, recent, or past infection) was significantly related with infants' antibody titers at birth. No other epidemiological or clinical factors were related to antibodies titers. Neurodevelopment, psychomotor development, and growth were normal in 94.2% of infants in the third follow-up visit. No infants had a COVID-19 diagnosis during the follow-up period.

CONCLUSIONS

Transplacental transfer of maternal antibodies is high in newborns from mothers with recent or past infection at delivery, but these antibodies decrease after the first months of life. Infant's IgG titers were related to maternal IgG titers at delivery. Further studies are needed to learn about the protective role of maternal antibodies in infants.

COVID-19 patient serum less potently inhibits ACE2-RBD binding for various SARS-CoV-2 RBD mutants

As global vaccination campaigns against SARS-CoV-2 proceed, there is particular interest in the longevity of immune protection, especially with regard to increasingly infectious virus variants. Neutralizing antibodies (Nabs) targeting the receptor binding domain (RBD) of SARS-CoV-2 are promising correlates of protective immunity and have been successfully used for prevention and therapy. As SARS-CoV-2 variants of concern (VOCs) are known to affect binding to the ACE2 receptor and by extension neutralizing activity, we developed a bead-based multiplex ACE2-RBD inhibition assay (RBDCoV-ACE2) as a highly scalable, time-, cost-, and material-saving alternative to infectious live-virus neutralization tests. By mimicking the interaction between ACE2 and the RBD, this serological multiplex assay allows the simultaneous analysis of ACE2 binding inhibition to the RBDs of all SARS-CoV-2 VOCs and variants of interest (VOIs) in a single well. Following validation against a classical virus neutralization test and comparison of performance against a commercially available assay, we analyzed 266 serum samples from 168 COVID-19 patients of varying severity. ACE2 binding inhibition was reduced for ten out of eleven variants examined compared to wild-type, especially for those displaying the E484K mutation such as VOCs beta and gamma. ACE2 binding inhibition, while highly individualistic, positively correlated with IgG levels. ACE2 binding inhibition also correlated with disease severity up to WHO grade 7, after which it reduced.

COVID-19 in people with rheumatic diseases: risks, outcomes, treatment considerations

The COVID-19 pandemic has brought challenges for people with rheumatic disease in addition to those faced by the general population, including concerns about higher risks of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and poor outcomes of COVID-19. The data that are now available suggest that rheumatic disease is associated with a small additional risk of SARS-CoV-2 infection, and that outcomes of COVID-19 are primarily influenced by comorbidities and particular disease states or treatments. Despite considerable advances in our knowledge of which therapeutic agents provide benefits in COVID-19, and of what constitutes effective vaccination strategies, the specific considerations that apply to people with rheumatic disease are yet to be definitively addressed. An overview of the most important COVID-19 studies to date that relate to people with rheumatic disease can contribute to our understanding of the clinical-care requirements of this population.

Cord Blood SARS-CoV-2 IgG Antibodies and Their Association With Maternal Immunity and Neonatal Outcomes

Passive transplacental immunity is crucial for neonatal protection from infections. Data on the correlation between neonatal immunity to SARS-CoV-2 and protection from adverse outcomes is scarce. This work aimed to describe neonatal seropositivity in the context of maternal SARS-CoV-2 infection, seropositivity, and neonatal outcomes. This retrospective nested case-control study enrolled high-risk pregnant women with a SARS-CoV-2 RT-PCR positive test who gave birth at the Instituto Nacional de Perinatología in Mexico City and their term neonates. Anti-SARS-CoV-2 IgG antibodies in maternal and cord blood samples were detected using a chemiluminescent assay. In total, 63 mother-neonate dyads (mean gestational age 38.4 weeks) were included. Transplacental transfer of SARS-CoV-2 IgG occurred in 76% of neonates from seropositive mothers. A positive association between maternal IgG levels and Cycle threshold (Ct) values of RT-qPCR test for SARS-CoV-2 with neonatal IgG levels was observed. Regarding neonatal outcomes, most seropositive neonates did not require any mechanical ventilation, and none developed any respiratory morbidity (either in the COVID-19 positive or negative groups) compared to 7 seronegative neonates. Furthermore, the odds of neonatal respiratory morbidity exhibited a tendency to decrease when neonatal IgG levels increase. These results add further evidence suggesting passive IgG transfer importance.

SARS-CoV-2 vaccine effectiveness in preventing confirmed infection in pregnant women

BackgroundSARS-CoV-2 infection in pregnancy is associated with a higher risk of pregnancy-related complications and neonatal respiratory distress and hospitalization. Effectiveness of SARS-CoV-2 vaccines in pregnant women is not known.MethodsAll women with confirmed pregnancy who presented to the national referral hospital in Qatar between December 20, 2020, and May 30, 2021, with at least 1 SARS-CoV-2 test and not testing prior to pregnancy were included. We determined the vaccine effectiveness of mRNA vaccines in preventing confirmed SARS-CoV-2 infection during pregnancy using both cohort and test-negative case-control designs. Analyses were adjusted for age group, nationality, and gestational age.ResultsAmong 4534 pregnant women, there were 407 vaccinated and 407 unvaccinated women in the matched cohort analysis. Vaccine effectiveness was 87.6% (95%CI 44.1%-97.2%) at least 14 days after the second dose. There were 386 test-positive and 834 matched women in the test-negative case control analysis. Vaccine effectiveness was 86.8% (95%CI 47.5%-98.5%) at least 14 days after the second dose. Adjustment for age, nationality, and gestational age yielded similar results for both designs. In the test-negative analysis, vaccine effectiveness at least 14 days after the first dose but before the second dose was 40.8% (95% CI 0.0%-80.4%). Of the 386 test-positive pregnant women, 74 cases were Alpha variant, 163 cases were Beta variant, and 156 cases were variants of unknown status. There were 9 severe or critical disease cases and no deaths in the test-positive pregnant women, all of whom were unvaccinated.ConclusionThe mRNA vaccines provide a high level of protection against documented SARS-CoV-2 infection, which supports the inclusion of pregnant women in vaccination campaigns.FUNDINGHamad Medical Corporation, Weill Cornell Medicine Qatar, and the Ministry of Public Health Qatar.