Peripartal anti-SARS-CoV-2-IgA/IgG in asymptomatic pregnant women during regional SARS-CoV-2-outbreak

SARS-CoV-2 Seroconversion and Pregnancy Outcomes in a Population of Pregnant Women Recruited in Milan, Italy, between April 2020 and October 2020

The possible link between SARS-CoV-2 infection and adverse pregnancy outcomes has so far demonstrated heterogeneous results in terms of maternal, fetal, and neonatal complications. We aim to investigate the correlation between SARS-CoV-2 seroconversion and/or neutralization titer and pregnancy outcomes. We analyzed a population of 528 pregnant women followed up from the first trimester of gestation until delivery. For each woman, we collected a first blood sample between 11 and 13 weeks of gestation and a second sample in the perinatal period (between peripartum and puerperium) to assess the presence of SARS-CoV-2 antibodies and/or microneutralization titer (MN titer). Data on pregnancy outcomes (gestational age at delivery, preterm birth before 34 weeks, hypertensive disorders, gestational diabetes, and abnormal fetal growth) were collected. We observed that serologic status per se is not associated with major pregnancy complications. On the contrary, the MN titer was associated with increased odds of gestational diabetes. Although we mainly reported asymptomatic SARS-CoV-2 infections and the absence of severe maternal and neonatal adverse outcomes, SARS-CoV-2 infection might challenge the maternal immune system and explain the moderate increase in adverse outcome odds.

Should pregnant women be screened for SARS-CoV-2 infection? A prospective multicenter cohort study

OBJECTIVE

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), ranges from asymptomatic to severe infection. We aimed to compare the prevalence of COVID-19 in asymptomatic pregnant versus nonpregnant women in order to establish recommendations for a COVID-19 screening strategy.

METHODS

A prospective multicenter cohort study was conducted. Asymptomatic pregnant or nonpregnant women after March 2020 (the time when COVID-19 was first detected in north Israel) were tested for SARS-CoV-2 using nasopharyngeal reverse transcription polymerase chain reaction test, anti-nucleocapsid IgG, and anti-spike IgG. Diagnosis was made if at least one test result was positive. Pregnant women were tested between 34 and 42 weeks, mostly at birth.

RESULTS

Among the 297 participating women, 152 were pregnant and 145 were nonpregnant. The prevalence of asymptomatic COVID-19 was similar between the groups (4 [2.6%] and 8 [5.5%], respectively; P = 0.2). All women with COVID-19 delivered healthy appropriate-for-gestational-age babies without malformations, at term.

CONCLUSIONS

The rate of asymptomatic COVID-19 in pregnant women is low and comparable to the rate among nonpregnant women. Pregnancy outcomes are favorable. Future screening programs should consider that one of 25 screened asymptomatic women will be positive.

SARS-CoV-2 in pregnancy and possible transfer of immunity: assessment of peripartal maternal and neonatal antibody levels and a longitudinal follow-up

OBJECTIVES

In the current Severe Acute Respiratory Distress Coronavirus 2 (SARS-CoV-2) pandemic there is still great uncertainty about the effects of an infection in pregnancy especially regarding a possible fetal transmission of antibodies to SARS-CoV-2 and the longevity of this immunity.

METHODS

Sixteen women who were infected with SARS-CoV-2 during pregnancy and their offspring were included. The antibody response to SARS-CoV-2 was measured in mother and umbilical cord blood peripartum and in a follow-up examination 6-11 weeks after birth. Medical history, symptoms regarding SARS-CoV-2, obstetric and neonatal information were queried following recommendations by the WHO.

RESULTS

A total of 73% of the women and one third of the infants developed antibodies to SARS-CoV-2 spike (S) protein receptor binding domain (RBD), with a long interval between infection and birth proving favorable for a transplacentar transfer of antibodies to the neonates. All infants showed declining or vanishing antibody-titers in the follow-up examination, while the titers of their mothers were stable or even increased.

CONCLUSIONS

Our results demonstrate that transplacental transfer of SARS-CoV-2-specific antibodies is possible, but also indicate that the immunity that may be gained as a result might decrease in newborns postpartum. This provides important evidence that could be useful for further studies covering vaccination during pregnancy.

Evaluation of the Clinical Performance of 7 Serological Assays for SARS-CoV-2 for Use in Clinical Laboratories

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serological assays have emerged as a response to the global pandemic, warranting studies evaluating their clinical performance. This study investigated seven commercially available SARS-CoV-2 serological assays in samples from non-infected individuals and hospitalized patients.

Methods

SARS-CoV-2 qualitative serological assays by Abbott (IgG), Beckman (IgG), DiaSorin (IgG), EUROIMMUN (IgG and IgA), Roche and Bio-Rad (Total) were evaluated using specimens collected pre-December 2019 (n=393), from nucleic acid amplification testing (NAAT) negative patients (n=40), and from 53 patients with COVID-19 by NAAT collected 3-21 days post-onset of symptoms (POS) (N=83). Negative agreement (NA), positive agreement (PA), and positive and negative predictive values (PPV and NPV) at prevalences of 5% and 10% were calculated.

Results

The overall %NA;95% CI in the negative samples were: Roche 99.8%; 99.3-100.2, Beckman 99.8%; 98.7-100.0, Abbott and Bio-Rad 99.3%; 98.0-99.9, DiaSorin 98.4; 97.2-99.6, EUROIMMUN IgG 97.5%; 95.5-98.7, and EUROIMMUN IgA 79.7%; 75.9-83.5), accounting for positive/equivocal results as false positives. The %PA; 95% CI in samples collected 14+days POS (n=24) were: Bio-Rad 83.3%; 68.4-98.2, Abbott and Roche 79.2%; 62.9-95.4, EUROIMMUN IgA 70.8%; 52.6-89.0, Beckman 58.3%; 38.6-78.1, DiaSorin 54.2; 34.2-74.1, and EUROIMMUN IgG 50.0%; 30.0-70.0, accounting for negative/equivocal results as false negatives. NPVs ranged from 97.4-98.9% and 94.7-97.7% for prevalences 5% and 10%, respectively. PPVs ranged from 15.5-94.8% and 27.9-97.4% for prevalences 5% and 10%, respectively.

Conclusions

The Roche and Beckman assays resulted in fewer false positives followed by the Bio-Rad and Abbott assays. While the Bio-Rad assay demonstrated higher antibody detection in COVID-19-positive patients, PA claims cannot be established with a high level of confidence in our sample population.