Parvovirus epidemic puts pregnant women at risk

David Baud, head of maternity at the CHUV in Lausanne, warned that in pregnant women this virus may represent a significant risk to the health of the foetus Keystone / Jean-christophe Bott

Scientists at the Lausanne University Hospital (CHUV) warned on Friday against the current epidemic of parvovirus in Switzerland and abroad. Often harmless, parvovirus poses a potentially serious risk to the foetus of pregnant women.

Parvovirus B19, often associated with erythema infectiosum, also known as the “fifth disease”, is often harmless in both adults and children. In children, it causes symptoms such as moderate fever, headaches, a cold or a rash on the arms, legs and body.

On the face, children develop a characteristic reddening of the cheeks. The disease is benign and passes spontaneously in a few days. Epidemics tend to occur in spring and are generally localised. The virus is transmitted by the respiratory tract, like Covid-19, RSV and influenza.

“In pregnant women, however, this virus may represent a significant risk to the health of the foetus,” David Baud, head of maternity at the CHUV, told the Swiss News Agency Keystone-ATS.

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When a woman contracts Parvovirus B19 during pregnancy, the virus can cross the placenta and infect the foetus. The most feared complication is foetal anaemia, which can lead to serious complications and even the loss of the foetus.

Heart problems

Parvovirus B19 can also affect the foetus’s cardiovascular system, increasing the risk of heart problems after birth. “We had to transfuse foetuses four times at the beginning of January 2024, which is already as many as in the whole of 2023,” Baud explained.

“Several mothers are currently being monitored for contact with infected children,” he added. Monitoring helps to reduce the risks to the pregnancy. It is therefore crucial to raise pregnant women’s awareness of this virus.

“We have sent information to all gynaecologists in French-speaking Switzerland,” Baud said. If a pregnant woman comes into contact with someone infected with the Parvovirus B19, it is essential that she informs her gynaecologist immediately. A simple blood test can show whether the patient is already protected and therefore risk-free.

Rebound effect

If the blood test shows a recent infection in the pregnant woman, a weekly ultrasound for three months can detect anaemia in the foetus and treat it with a transfusion if necessary.

The current epidemic may be due to the fact that the virus circulated very little during Covid and that many young children were not immunised, according to Baud. So it could now be a case of a rebound effect.

Outbreaks have also been observed in other countries, notably France and Israel. “All European countries seem to be concerned,” Baud said.

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