VERTICAL TRANSMISSION OF SARS-COV-2 DURING PREGNANCY : A PROSPECTIVE ITALIAN COHORT STUDY

OBJECTIVE: THE EXTENT OF VERTICAL TRANSMISSION ( VT ) OF SARS-COV-2 FROM MOTHERS TO NEONATES IS STILL UNCERTAIN. WE AIMED TO DETERMINE THE INCIDENCE OF VT. STUDY DESIGN: IN THIS PROSPECTIVE COHORT STUDY ALL MOTHER DIAGNOSED WITH SARS-COV-2 INFECTION AT TIME OF DELIVERY OR UP TO ONE WEEK PRIOR AND THEIR NEONATE MANAGED IN A TERTIARY REFERRAL HOSPITAL FOR PREGNANCY COMPLICATED BY COVID-19 IN ROME, FROM APRIL 2 TO DECEMBER 22,2020,WERE INCLUDED.MATERNAL INFECTION WAS DEFINED AS NASOPHARYNGEAL SWAB TEST RESULTS POSITIVE FOR SARS-COV-2 RT-PCR. BIOLOGICAL SAMPLES WERE COLLECTED BEFORE, AT, AND AFTER DELIVERY TO TEST POSITIVITY FOR SARS-COV-2 RT-PCR AND ANTI SARS-COV-2 SPECIFIC ANTIBODIES. RESULTS: THE COHORT INCLUDED 95 WOMEN AND 96 NEONATES WITH DOCUMENTED SARS-COV-2 TEST RESULTS. FOUR NEONATES ( 4.2% ) TESTED POSITIVE. THE INCIDENCE OF VT, ACCORDING TO THE GUIDANCE CRITERIA FOR DIAGNOSING PERNATAL SARS-COV-2 INFECTION,WAS 5.2%. NEONATAL SYMPTOMS WERE DUE TO PREMATURITY OR FETAL DISTRESS: SYMPTOMATIC INFANTS HAD LOWER MEDIAN [ MIN-MAX ] GESTATIONAL AGE ( 38.1 [29.3-40.6] VS 39.3 [33.9-41.9] WEEKS ; P= .036), 1-MIN ( 9[3-9]VS 9[7-10]; P= .036), AND 5-MIN APGAR SCORES (10[6-10] VS 10[8-10]; P= .012) THAN ASYMPTOMATIC INFANTS, AND NEEDED MORE FREQUENTLY ASSISTANCE IN THE DELIVERY ROOM ( 22.2% VS 2.5%; P= .0089. ONLY 6(7.1%) NEONATES HAD ANTI SARS-COV-2 SPECIFIC ANTIBODIES,DESPITE THE ONGOING MATERNAL INFECTION. CONCLUSIONS: THE INCIDENCE OF VT IS LOW AS IS THE DETECTION OF SPECIFIC ANTI SARS-COV-2 ANTIBODIES IN CORD BLOOD WHEN INFECTION IS CONTRACTED LATE IN PREGNANCY.THIS WOULD SUGGEST POOR PROTECTION OF INFANTS AGAINST HORIZONTAL TRANSMISSION OF THE VIRUS