Possible vertical transmission of coronavirus

While it is widely recognized that person-to-person contact is the most common form of coronavirus (SARS-CoV-2) transmission, a new research letter published in JAMA Network suggests that vertical transmission may be possible. The authors note, however, that this is just one case, and prior to this report, a series of nine infected pregnant women found no transmission to their newborns.

On January 28, 2020, a 29-year-old primiparous woman (34 weeks 2 days gestation) suspected of being exposed to SARS-CoV-2 developed a temperature of 100.2˚F and presented with nasal congestion that progressed to respiratory difficulty. On January 31, a chest computed tomography (CT) scan showed the ground-glass opacities associated with SARS-CoV-2 in both lungs. A real-time reverse transcriptase–polymerase chain reaction (RT-PCR) for SARSCoV-2 nucleic acid of nasopharyngeal swab of the nasal cavity also tested positive.

On February 2, the patient was admitted to Renmin Hospital in Wuhan, China and received antibiotic, antiviral, corticosteroid, and oxygen therapies. Results from four repeat RT-PCR tests were positive. IgG and IgM antibody levels to SARS-CoV-2 were 107.89 AU/mL and 279.72 AU/mL, respectively (normal IgM and IgG < 10AU/mL) on February 21. However, results from RT-PCR testing of the patient’s vaginal secretions were negative.

On February 22, the patient delivered an infant girl via cesarean in a negative-pressure isolation room. The mother wore an N95 mask and did not hold the infant. The infant weighed 3120 g and her Apgar scores were 9 and 10 at 1 and 5 minutes, respectively. The infant had no symptoms of SARS-CoV-2 but was immediately quarantined in the neonatal intensive care unit (NICU).       

At 2 hours of age, the infant’s SARS-CoV-2 IgG level was 140.32/AUmL and her IgM level was 45.83 AU/mL. Her cytokines were also elevated (IL-6 = 28.26 pg/mL; IL-10 = 153.60 pg/mL) and her white blood cell count was 18.08 x 10⁹/L. The infant’s chest CT was normal. The neonate was transferred to a children’s hospital. Five RT-PCR tests on nasopharyngeal swabs taken from 2 hours to 16 days of age were all negative. By March 7, the infant’s IgM (11.75 AU/mL) and IgG (69.94 AU/mL) levels were still elevated. By March 18, she was discharged.

On February 28, the mother’s breast milk had a negative RT-PCR test result and the next day her IgG level was 116.30 AU/mL and IgM level was 112.66 AU/mL. A chest CT scan showed moderate resolution of the ground glass opacities.

The authors believe their findings indicate that the neonate was infected with the virus in utero. The infant potentially could have been exposed for 23 days from the time of the mother’s diagnosis to the time of delivery. Lab results indicating inflammation and liver injury also support vertical transmission. Although infection at delivery cannot be completely ruled out, IgM antibodies do not appear until 3 to 7 days after infection, and the neonate displayed elevated IgM levels at 2 hours after birth. However, the authors note that this is still just one case and more maternal and neonatal testing needs to be done.