Press release
Lausanne, 5 novembre 2021

The human placenta, a target of SARS-CoV-2

What happens in the human placenta after SARS-CoV-2 infection? Research teams led by Dr Marco Alves (Institute of Virology and Immunology IVI, Bern) and Prof David Baud (Lausanne University Hospital, CHUV) found that SARS-CoV-2 can infect the cells of human placenta and that the virus proliferates and infects neighbouring pla-cental cells. The results of their research work have been recently published in the scientific journal Cell Reports Medicine (Fahmi et al, 2021).

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« This is a major advance in our understanding of COVID-19 during pregnancy », explains Marco Alves, group leader and immunologist at the IVI. « Thousands of infectious viral particles can be produced rapidly in the placenta. In addition, we observed that expression of the SARS-CoV-2 receptor in the placenta is highly variable and specific to each pregnancy, which might explain why the virus sometimes is transmitted to the foetus ».

It is important to remember that pregnant women have a 70% greater risk of becoming infected with SARS-CoV-2 than the general population of the same age. « If they become infected, the risk of a severe progression, i.e. admission to intensive care, is around five to ten percent », explains David Baud, head of obstetrics at the CHUV. The risk of premature delivery is increased by two to three times. It is also known that the risk of foetal death (death in utero) similarly increases by two to three times if the pregnant woman is infected. Pregnant women and their unborn children should therefore be considered as especially vulnerable to SARS-CoV-2.

The study by the Bern and Lausanne research teams strengthens the recommendation of vaccination for pregnant women. To date, several hundred thousand pregnant women have received a messenger RNA vaccine, with no increase in risk to mother and child. Indeed, messenger RNA does not pass into the foetus, while the antibodies developed by the mother cross the placental barrier and will therefore protect the child. “The fact that the virus can infect and proliferate in the placenta demonstrates the need for women to be vaccinated”, say the two researchers. Vaccination against SARS-CoV-2 is currently recommended for all pregnant women in Switzerland.

More information
Institute of Virology and Immunology IVI : communication(at)ivi.admin.ch / +41 58 481 38 88
CHUV : medias(at)chuv.ch /+41 79 556 60 00

About Institute of Virology and Immunology
The Institute of Virology and Immunology (IVI) is the federal institute for the diagnosis, monitoring and research of highly infectious and important epizootic diseases of viral origin, including viral zoonoses. As part of a cooperation agreement with the Vetsuisse faculty of the University of Bern, the IVI is also responsible for teaching in the fields of virology and immunology. The IVI reports to the Federal Food Safety and Veterinary Office (FSVO).

About Lausanne University Hospital (CHUV)

CHUV is one of Switzerland’s five university hospitals, alongside Geneva, Bern, Basel and Zurich. It is tasked with three basic missions by the public authorities, namely care, teaching and research. It provides care in all areas of medicine, including physical disorders and psychiatric illnesses, medical and surgical disciplines, outpatient and inpatient treatment.

In 2021, CHUV’s 12,228 employees cared for 51,205 inpatients, accounting for over 500,374 days of hospitalisation. It dealt with 80,261 emergencies, provided 1,451,300 outpatient consultations and welcomed 3,177 new babies into the world. Its annual budget is 1.832 billion Swiss francs.

CHUV works closely with the Faculty of Biology and Medicine of the University of Lausanne to provide undergraduate, postgraduate and continuing education for doctors. It also works with other higher education institutions in the Lake Geneva area (including EPFL, ISREC, the Ludwig Institute for Cancer Research and the University of Geneva), with the University Hospitals of Geneva and other hospitals, health care providers and institutions, such as the Federation of Vaud Hospitals and the Vaud Society of Medicine.

Since 2019, CHUV has been ranked as one of the best hospitals in the world according to Newsweek magazine.