SARS-CoV-2 Infection of the Placenta

Authors: Hosier and Farhadian et al

Link to paper: https://www.medrxiv.org/content/10.1101/2020.04.30.20083907v2.full

Journal/ Pre-Print: medRxiv

Tags Clinical; Pregnancy

Research Highlights 

1. SARS-CoV-2 infection reported in the placenta during second trimester pregnancy

Summary 

Hosier and Farhadian et al present the findings of a single patient case study of SARS-CoV-2 infection during the second trimester of pregnancy. The patient, who tested positive for SARS-CoV-2 through nasopharyngeal swab, experienced a retroplacental clot and severe preeclampsia which led to the termination of pregnancy. qRT-PCR analysis detected SARS-CoV-2 RNA in the placenta but not fetal heart and lung tissues despite high maternal antibody titers. Further histological analysis revealed notable macrophage infiltrate alongside fibrin deposits in the placenta. The detection of SARS-CoV-2 RNA coupled with inflammatory infiltrate suggests SARS-CoV-2 can infect the placenta. This may lead to severe complications in pre-disposed SARS-CoV-2 infected pregnant women and raises many questions for the field.

Impact for SARS-CoV2/COVID19 research efforts

Understand the virology and/or cell biology of SARS-CoV2/COVID19

Analysis of placental and foetal tissue provides information on the potential tissue tropism of SARS-CoV-2

Clinical symptoms and pathogenesis of SARS-Cov2/COVID19

Single patient case study specifically reports the symptoms and pathogenesis of SARS-CoV-2 infection during the second trimester of pregnancy

Study Type

· Patient Case study

Strengths and limitations of the paper

Novelty: First report of SARS-CoV-2 detected in the placenta

Standing in the field: Lack of SARS-CoV-2 in foetal tissues supported by lack of SARS-CoV-2 RNA detected in amniotic fluid in 2 SARS-CoV-2 infected women also in the second trimester of pregnancy (https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30320-0/fulltext).

Appropriate statistics: Statistics not possible due to single patient case study

Viral model used: Case study of SARS-Cov-2 infection, confirmed by CDC qRT-PCR

Translatability: Provides information on SARS-CoV-2 infection during pregnancy and presents evidence that COVID19 may impact on the course of pregnancy and maternal health. This supports policies that pregnant women, especially those with a history of preeclampsia, should be shielded from SARS-CoV2. Provides data for potential vertical transmission of SARS-CoV-2, as despite being detected in the placenta, foetal tissues were SARS-CoV-2 negative.

Main limitations:

· Single patient study. Case report

· Ability to draw conclusions complicated by the fact patient had term gestational hypertension in previous pregnancy