Rubella – colloquially called German measles – (synonyms: German measles; rubella (rubella); rubella virus infection; rubeola; rubeola; rubella; ICD-10 B06.-: Rubella [rubeola] [rubella]) is among the classic childhood diseases. It is a viral infection with the rubella virus, which occurs in 80-90% of cases in childhood if not vaccinated against. The causative agent is a rubivirus (= RNA virus) from the Togavirus/Togaviridae family. Occurrence: The infection occurs worldwide. The so-called contagiousness index (synonyms: contagiousness index; infection index) was introduced to mathematically quantify the contagiousness (infectiousness or transmissibility of the pathogen). It indicates the probability with which a non-immune person becomes infected after contact with a pathogen. The contagiousness index for rubella is 0.15-0.2, which means that 15-20 out of 100 unvaccinated persons become infected after contact with a rubella-infected person.Manifestation index: Approximately 30-50% of rubella-infected persons become recognizably ill with rubella. The transmission of the pathogen (infection route) occurs via droplets, which are produced during coughing and sneezing and are absorbed by the opposite person via the mucous membranes of the nose, mouth and possibly the eye (droplet infection) or aerogenically (through droplet nuclei (aerosols) containing the pathogen in the exhaled air) with 50% contagiosity (infectiousness or transmissibility of the pathogen). The incubation period (time from infection to onset of disease) is usually 14-21 days. A distinction is made between:
- Postnatally acquired rubella – infection acquired after birth; is usually asymptomatic (i.e., without symptoms); if it becomes clinically manifest, there is usually a mild clinical picture with fever and diffuse small-spotted exanthema (rash)
- Prenatal/congenital rubella / congenital rubella embryofetopathy (very rare) – infection of the unborn child in the womb by the mother.
- Probability of infection in the first eight weeks of pregnancy: 90%.
- Probability of infection in the second trimester (third trimester): 25-35%.
Rubella embryopathy rates and occurrence of malformations depending on the timing of rubella in pregnancy see below “Rubella / sequelae”. Frequency peak: the disease occurs predominantly in schoolchildren. The duration of infectivity (contagiousness) is from one week before the appearance of the exanthema (skin rash) to about one week after the appearance of the exanthema. The incidence (frequency of new cases) of postnatal rubella is approximately 1 case per 100,000,000 inhabitants per year (in the new German states; however, under-reporting must be assumed). The disease leaves lifelong immunity. If the vaccination or initial infection occurred a very long time ago, a new infection may occur (very rare). Course and prognosis: The disease is often asymptomatic (without noticeable symptoms) and therefore remains unnoticed. In children, the course is usually mild. In adults, however, complications such as arthritis (inflammation of the joints), encephalitis (inflammation of the brain), and myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the pericardium) may occur. Infection during gravidity (pregnancy) may result in abortion (miscarriage) or rubella embryopathy (resulting in organ damage/disability) and rubella syndrome of the newborn. Postnatal infections (reports for 2015 according to RKI: n = 12) and associated children with rubella embryopathy have become very rare (< 1 case per 100,000 live births).Rubella embryopathy rates and occurrence of malformations depending on the timing of rubella in pregnancy see below “Rubella/Subsequent diseases”. Vaccination: Vaccination against rubella is available. In Germany, direct or indirect detection of the pathogen is reportable according to the Infection Protection Act (Infektionsschutzgesetz, IfSG), as far as the evidence indicates an acute infection.