Persistence of SARS-CoV-2 RNA Residues in Placenta Tissue Following Maternal COVID-19 Infection During Pregnancy.
Prolonged SARS-CoV-2 viral persistence was reported in extrapulmonary tissues in patients infected with COVID-19. SARS-CoV-2 can infect placental tissue. However, little is known about SARS-CoV-2 viral persistence in the placenta.
This is a retrospective and IRB approved study. Placental tissue samples from 40 women infected with COVID-19 at various gestational age were analyzed. SARS-CoV-2 RNA expression was examined by in situ hybridization on placental disk and fetal membrane. S-protein and N-protein expression was determined by immunostaining. SARS-CoV-2 RNA sequencing was also performed in 12 out of the 29 cases in which SARS-CoV-2 RNA expression was detected positive by in situ hybridization.
SARS-CoV-2 RNA expression was detected in placental disk, predominantly localized in syncytiotrophoblasts in 29 out of the 40 cases, but not in fetal membrane. Among the 29 positive cases, 4 infected in the first trimester, 7 in the second trimester, and 18 in the third trimester or at term. The longest interval from infection to delivery was 221 days. Among the 21 women who tested positive for COVID-19 at L/D admission, 18 (85.7%) detected SARS-CoV-2 RNA expression in placental tissue. Notably, 11 (57.9%) of 19 cases (negative test at L/D admission) detected viral RNA expression in placental villous tissue. Viral RNA expression was also detected in villous core vessel endothelium in two COVID (+) newborn placentas, with corresponding positive S-protein and N-protein expression in syncytiotrophoblasts. S-protein and N-protein expression was undetectable in 27 out of the 29 cases with positive detection of SARS-CoV-2 RNA expression. Partial RNA-dependent RNA polymerase (RdRp) region sequence was identified in all the 12 cases examined.
These findings provide compelling evidence that SARS-CoV-2 genetic material can persist in placental tissue long after maternal infection, which may potentially contribute to a sustained inflammatory environment at the maternal-fetal interface during pregnancy. The phenomenon of partial RdRp sequence detected would provide a possible explanation for undetectable S- and N-protein expression in testing specimens.
This is a retrospective and IRB approved study. Placental tissue samples from 40 women infected with COVID-19 at various gestational age were analyzed. SARS-CoV-2 RNA expression was examined by in situ hybridization on placental disk and fetal membrane. S-protein and N-protein expression was determined by immunostaining. SARS-CoV-2 RNA sequencing was also performed in 12 out of the 29 cases in which SARS-CoV-2 RNA expression was detected positive by in situ hybridization.
SARS-CoV-2 RNA expression was detected in placental disk, predominantly localized in syncytiotrophoblasts in 29 out of the 40 cases, but not in fetal membrane. Among the 29 positive cases, 4 infected in the first trimester, 7 in the second trimester, and 18 in the third trimester or at term. The longest interval from infection to delivery was 221 days. Among the 21 women who tested positive for COVID-19 at L/D admission, 18 (85.7%) detected SARS-CoV-2 RNA expression in placental tissue. Notably, 11 (57.9%) of 19 cases (negative test at L/D admission) detected viral RNA expression in placental villous tissue. Viral RNA expression was also detected in villous core vessel endothelium in two COVID (+) newborn placentas, with corresponding positive S-protein and N-protein expression in syncytiotrophoblasts. S-protein and N-protein expression was undetectable in 27 out of the 29 cases with positive detection of SARS-CoV-2 RNA expression. Partial RNA-dependent RNA polymerase (RdRp) region sequence was identified in all the 12 cases examined.
These findings provide compelling evidence that SARS-CoV-2 genetic material can persist in placental tissue long after maternal infection, which may potentially contribute to a sustained inflammatory environment at the maternal-fetal interface during pregnancy. The phenomenon of partial RdRp sequence detected would provide a possible explanation for undetectable S- and N-protein expression in testing specimens.
Authors
Gu Gu, Xu Xu, Gu Gu, Lewis Lewis, Queen Queen, Scott Scott, Zoorob Zoorob, Vanchiere Vanchiere, Wang Wang
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