Parvovirus B19 in France: what symptoms? In adults?

A epidemic infections Parvovirus B 19 is currently touching France, particularly very young children. Started in spring 2023, this epidemic “continues its rise in 2024 with a peak that has not yet been reached” noted Public Health France on April 22. Perinatal services report a increase in miscarriages and of fetal deaths related to this virus. The health agency informs of the death 5 children under the age of one year including 4 newborns, since the beginning of 2024. “THE reasons for this epidemic are not clearly established, but as with other viral or bacterial infections, it could be linked to the lifting of health measures (in particular confinement and barrier measures) which followed the Covid-19 pandemic during which an immune debt was able to set in” explains the authority. An increase in the number of Parvovirus B19 infections has also been reported in other European countries including DenmarkIreland, the Netherlands and Norway.

What is Parvovirus B 19?

Parvovirus B 19 is a strictly human virus which is transmitted mainly by the respiratory route, more rarely by the blood route. It belongs to the Parvoviridae family. “B 19” correspond to the initials identifying the blood bag where it was first found, it was in 1975. Parvovirus B 19 causes an infection that is most often benign and asymptomatic, that is to say without symptoms. It can otherwise be responsible for infectious erythema also called “epidemic megaerythema”, “fifth disease” or even “slapped cheek syndrome” (because the child has very red cheeks). Infections occur in epidemics more often at the end of winter and at the beginning of spring. There is no particular prevention to avoid contagion but contact with pregnant women and people with fragile health should be avoided. Expulsion from school is not recommended.

What symptoms?

After 4 to 21 days (3 weeks) of incubation, the first clinical signs of infection appear. First a low fever, fatigue, sometimes nasopharyngitis then a characteristic rash on the face :

• the cheeks are very red (like after a slap)
• the rash goes down the trunk and extremities, in the form of small pinkish bands or macules

The person is already contagious before the rash phase. The doctor can confirm the diagnosis with a blood test.

Same in adults?

In adults, Parvovirus B19 infection is mainly manifested by joint symptoms. These are present in 70% of adults compared to 10% of children. Women are at greater risk of infection than men, especially those aged 20 to 40. They will suffer from joint pain, especially in their hands, wrists, ankles and knees. This pain generally disappears within 2 to 3 weeks. Recurrent outbreaks are not impossible in the years following infection.

What dangers?

Parvovirus B19 infection is particularly dangerous in people with chronic anemia, immunocompromised people and pregnant women. In the latter, the virus present in the amniotic fluid can cause miscarriages and fetal anasarca, a severe fetal disease. The virus is also dangerous for the heart, myocarditis or encephalitis can sometimes be observed.

In France, the number of deaths linked to Parvovirus B 19 infection is on average 1.8 deaths/year (2015-2019), including 78% among people aged 15 or over. This number doubled over the period 2020-2023. Since the beginning 2024, 5 deaths have already been identified, all involving children. For four of them, it is a death occurring in the very first days of life linked to maternal-fetal infection. For the fifth death (8 months old), there was no comorbidity or immunosuppression. There are no vaccines or treatments specific to the infection except paracetamol in uncomplicated forms. For more serious cases, hospitalization is necessary and a transfusion may be warranted.