ABSTRACT
Objective: To evaluate if SARS-CoV-2 is detectable in vaginal
swabs and whether antibodies against SARS-CoV-2 are present in maternal
and umbilical cord blood of pregnant women with COVID-19.
Design: Prospective cohort study.
Setting: Department of Obstetrics and Gynaecology, Copenhagen
University Hospital – North Zealand, Denmark.
Population: Pregnant women tested positive for SARS-CoV-2 in a
pharyngeal swab between August 20th, 2020 and March
1st, 2021 who gave birth during the same period.
Methods: Maternal blood sample and vaginal swabs were collected
at inclusion. If included during pregnancy, these samples were repeated
at delivery in addition to an umbilical cord blood sample. Swabs were
analysed for SARS-CoV-2 and blood samples for SARS-CoV-2 total
antibodies. Placental and neonatal swabs were performed on clinical
indications.
Main outcome measures: SARS-CoV-2 in vaginal swabs and
SARS-CoV-2 total antibodies in maternal and umbilical cord blood.
Results: We included 28 women, hereof 4 serious maternal or
fetal outcomes including 1 neonatal death. Within the first eight days
after a maternal positive pharyngeal swab, SARS-CoV-2 was detectable in
two vaginal (2/28) and two placental swabs (2/4), whereas SARS-CoV-2
antibodies were detected in 1/13 women. After eight days, SARS-CoV-2 was
not detectable in vaginal swabs and SARS-CoV-2 antibodies were observed
in 19/21 of women. Antibodies in cord blood of seropositive mothers
appeared after 16 days.
Conclusion: Vertical transmission of SARS-CoV-2 seems plausible
since SARS-CoV-2 is detectable in the vagina up to eight days after a
positive pharyngeal swab at which time the neonate is not yet protected
by antibodies.
Funding: The Research Foundation, North Zealand Hospital and
Ferring
Keywords : Severe acute respiratory syndrome coronavirus 2;
COVID-19; Obstetric delivery; Pregnancy complications; Pregnancy
outcome; Placental dysfunction; Vertical transmission; Cohort studies;
Prospective studies
Tweetable abstract: Vertical transmission of SARS-CoV-2 is
plausible within the first week of maternal COVID-19.