Large patches of redness, first on the cheeks and later on the rest of the body: This is typical for rubella. An unusually high number of cases have been reported in Germany and the EU since January. What you need to know about the infection and who is particularly at risk.

Rubella is particularly common in daycare centers and schools in winter and spring. More precisely: the parvovirus B 19, which causes this disease. It is transmitted primarily via fine droplets of saliva that get into the air when you cough, for example, as pediatric and adolescent medicine specialist Patrick Hundsdörfer from the Helios Klinikum Berlin-Buch explains.

The number of reported cases of rubella has increased significantly in Germany and several other EU countries since the beginning of the year. Although infections with the parvovirus B19 usually only occur more frequently in spring and early summer, there was already a significant increase in incidence in this country between January and March, says Martin Enders from the consulting laboratory for parvoviruses in Stuttgart.

By the way, rubella has nothing to do with rubella. What families still need to know:

A skin rash that appears one to two weeks after infection is typical. First, butterfly-shaped, large patches of redness appear on the cheeks, as Hundsdörfer describes. One or two days later, such redness can also be observed on the shoulders, upper arms, thighs and buttocks, sometimes stretching like garlands around the limbs.

There may also be symptoms that are similar to those of a flu-like infection: fever, malaise, headache. In many cases, rubella remains unnoticed and does not cause any symptoms.

The rash usually does not need to be treated. The redness fades after seven to ten days and then disappears, says Hundsdörfer.

If the child has a fever or complains of muscle and joint pain, medications such as ibuprofen and paracetamol can help. As a rule, rubella in children is harmless.

Yes, but only if you have not previously had a rubella infection. 50 to 80 percent of adults have had rubella in their lives, writes the portal “gesund.bund.de”. So you are immune.

Good to know: Once the typical skin rash appears, the infected person only poses a low risk of infection. It mainly occurs in the days before – when the infection is often still unnoticed. Even if you have no symptoms, you are still contagious. If adults become infected, the symptoms are often more severe than in children.

There are risk groups for whom rubella can become a major problem: In addition to people with blood diseases or immunosuppression (immune deficiency), these are primarily pregnant women who have not yet been infected. The virus can be transmitted to the unborn child, and there is a risk of life-threatening damage to its blood formation, as Hundsdörfer warns.

As a result of the currently very high incidence, B19V-related fetal complications during pregnancy such as miscarriages (abortion) and fluid accumulation (hydrops) are being reported more frequently, says Martin Enders. The following non-representative case numbers, diagnosed in the Stuttgart laboratory (as of April 26th), were counted for the first three months of the year: more than 120 cases in January, around 150 in February and more than 240 in March. According to Enders, the complications most often occur in infections before the 20th week.

Pregnant women pass the rubella pathogen on to their unborn child, even if the infection goes unnoticed. The viruses enter the child’s bloodstream via the placenta and attack blood-forming cells – the result can be anemia in the unborn child. In the worst case scenario, there is a risk of miscarriage or premature birth, especially in the first few months of pregnancy.

“Some pregnant women show typical symptoms such as coughing, a runny nose and then a rash. But this is not always the case,” says the federal spokesman for the professional association of pediatricians and adolescents, Jakob Maske. There are hardly any similar diseases that lead to a rash as specific as that caused by rubella. “Of course there are allergic reactions that can look similar. But they usually have other symptoms.”

Karl Oliver Kagan, head of prenatal medicine at the University Women’s Clinic in Tübingen, also speaks of many pregnant women who are currently infected with parvovirus B19 and come to the clinic for treatment or check-ups. However, it cannot be said how many people are actually infected because not everyone affected developed symptoms. If a pregnant woman wants to know whether she has ever had rubella in the past and is possibly immune, she can get tested – for example if there has been contact with an infected person. This test looks for antibodies against the parovirus B19 and, if necessary, for virus genetic material in the blood.

According to Kagan, if the mother is infected with rubella, it is assumed that around ten percent of the unborn children will become infected. In pregnant women who were infected in the first half of pregnancy, it should be clarified whether the infection is causing childhood anemia. “In the case of anemia, the unborn child needs a blood supply that can be administered externally via the umbilical cord. Given the small diameter of the umbilical cord, this therapy is challenging and is actually only possible from the 16th week of pregnancy,” says Kagan. After hardly any transfusions had to be carried out in the Tübingen women’s clinic in recent years due to rubella infections, there are now around two per week.

In the first weeks of pregnancy, there is no way to detect an infection or anemia in the embryo. In some cases, anemia can be detected in the first trimester screening in the twelfth or thirteenth week of pregnancy, but it is still too early for a blood transfusion. “An infection in the last trimester of pregnancy usually does not pose a life-threatening risk to the unborn child,” explains Kagan.

According to Enders, the exceptionally strong activity can be explained, among other things, by the fact that the number of cases was very low during the pandemic due to lockdowns and hygiene measures and that there is now a significantly higher number of susceptible hosts available to the virus. “From the beginning of 2020 to the beginning of 2023, we basically had no activity or only minimal activity for three years. “That means a lot of children have accumulated who are not immune and that’s what’s going on now,” says Enders. More infections in children automatically meant more infections in pregnant women – and therefore more complications. “But I don’t think that the virus has changed in any way and that the infections are therefore more severe.”

The EU health authority ECDC recently reported an increase in the number of parvovirus B19 infections in Denmark, Ireland, the Netherlands, Norway and France. Although a detailed epidemiological analysis is lacking because the disease is not monitored in most countries, the data showed increased infection rates in several age groups, with young children particularly affected.