The clinical impact of maternal COVID-19 on mothers, their infants, and placentas with an analysis of vertical transfer of maternal SARS-CoV-2-specific IgG antibodies (preprint)

Introduction: The effect of SARS-CoV-2 infection on pregnant mothers, the placenta, and infants is not fully understood and sufficiently characterized. Methods: We performed a retrospective, observational cohort study in Chapel Hill, NC of 115 mothers with SARS-CoV-2 and singleton pregnancies from December 1, 2019 to May 31, 2021. We performed a chart review to document the infant weight, length, head circumference, survival, congenital abnormalities, and hearing loss, maternal complications, and placental pathology classified by the Amsterdam criteria. Results: The average infant weight, length, and head circumference were all within the normal range for gestational age, the infants had no identifiable congenital abnormalities, and all infants and mothers survived. Only one infant (0.870%) became infected with SARS-CoV-2. Moderate and severe maternal COVID-19 were associated with increased caesarean section, premature delivery, infant NICU admission, and maternal respiratory failure, and were more likely in Type 1 (p=0.0055) and Type 2 (p=0.0285) diabetic mothers. Most placentas (n=63, 54.8%) showed normal or non-specific findings, while a subset had mild maternal vascular malperfusion (n=26, 22.6%) and/or mild microscopic ascending intrauterine infection (n=28, 24.3%). Discussion: Most mothers with SARS-CoV-2 and their infants had a routine clinical course. Maternal SARS-CoV-2 infection was not associated with intrauterine fetal demise, infant death, congenital abnormalities, or hearing loss. Infant infection with SARS-CoV-2 was rare and not via the placenta. Most placentas had non-specific findings and a subset showed mild maternal vascular malperfusion and/or mild microscopic ascending intrauterine infection, which were not associated with maternal COVID-19 severity.

Longitudinal SARS-CoV-2 testing is punctuated by intermittent positivity and variable rates of cycle-threshold decline (preprint)

The COVID-19 pandemic is complicated by cases of vaccine-breakthrough, re-infection, and widespread transmission of variants of concern (VOC). Consequently, the need to interpret longitudinal positive SARS-CoV-2 (SCV-2) tests is crucial in guiding clinical decisions regarding infection control precautions and treatment. Although quantitative tests are not routinely used diagnostically, standard diagnostic RT-PCR tests yield Ct values that are inversely correlated with RNA quantity. In this study, we performed a retrospective review of 72,217 SCV-2 PCR positive tests and identified 264 patients with longitudinal positivity prior to vaccination and VOC circulation. Patients with longitudinal positivity fell into two categories: short-term (207, 78%) or prolonged (57, 22%) positivity, defined as <= 28 (range 1-28, median 16) days and >28 (range 29-152, median 41) days, respectively. In general, Ct values declined over time in both groups; however, 11 short-term positive patients had greater amounts of RNA detected at their terminal test compared to the first positive, and 5 patients had RNA detected at Ct < 35 at least 40 days after initial infection. Oscillating positive and negative results occurred in both groups, although oscillation was seen three times more frequently in prolonged-positive patients. Patients with prolonged positivity had diverse clinical characteristics but were often critically ill and were discharged to high-level care or deceased (22%). Overall, this study demonstrates that caution must be emphasized when interpreting Ct values as a proxy for infectivity, predictor of severity, or a guide for patient care decisions in the absence of additional clinical context.