Rubella is an infectious exanthematous disease caused by a virus, the Rubivirus, capable of localising in various tissues including the lymph nodes.
The disease most commonly affects children.
Once rubella has been contracted, it confers lifelong protection against subsequent infections (immunity); the vaccine also gives a long-lasting immunity.
Rubella is transmitted from an infected individual to a healthy susceptible person through the droplets emitted by coughing, sneezing or simply speaking. The virus is able to cross the placenta, thus a woman who contracts rubella during pregnancy can transmit the infection to the embryo or foetus.
Those infected can transmit the disease to healthy susceptible people in the period from a week before to 4 days after the onset of the exanthema. Newborns who contract the infection in the womb can transmit the virus for several months.
Symptoms and complications
The incubation period lasts about 16-18 days. Symptoms are often mild and up to 50% of infections are inapparent. In children, the first manifestation of the disease is usually the exanthema, which is rarely preceded by other symptoms. In boys and adults, the exanthema is usually preceded by 1-5 days of low-grade fever, malaise, lymphadenopathy and upper respiratory tract symptoms.
Subsequently, small pink or pale red spots begin to appear, initially behind the ears, later on the face and neck and then spreading to the rest of the body. This rash disappears within two or three days. The exanthema is made more noticeable by a hot bath or shower, but the rash does not appear in about 40% of cases, while in 20-25% of cases the only symptoms are fever and swollen lymph nodes. Rubella, therefore, manifests in only about 50% of cases.
Rubella complications are not common, but occur more often in adults than in children.
- Arthralgia or arthritis: up to 70% of adult women who contract rubella can develop these conditions, while they are rare in children and adult males. The body parts most affected are fingers, wrists and knees. Symptoms appear at the same time as the rash and can last for up to 1 month.
- Encephalitis: occurs in one in 6,000 cases, more frequently in adults. Estimates of mortality range from 0 to 50%.
- Haemorrhagic manifestations: these occur in about one in every 3,000 cases, more often in children, due to damage to blood vessels and platelets. The effects can last from days to months, and most patients recover.
Other complications include orchitis, neuritis, and a rare syndrome called progressive rubella panencephalitis.
If rubella is contracted by a woman during pregnancy, all foetal organs and tissues are affected with potentially very serious consequences: miscarriage; intrauterine death of the foetus; malformations and inflammatory lesions, mainly affecting the nervous system, the cardiovascular system, the sense organs, with delayed physical and mental development (Congenital rubella syndrome).
The risk of serious foetal malformations is greater when rubella is contracted during the first trimester of pregnancy (85% in the first 8 weeks, 52% from the ninth to the twelfth week of gestation), while infections contracted after the twentieth week rarely cause congenital malformations.
Congenital rubella syndrome is characterised by:
- Developmental delay
- Congenital heart diseases
- Damage to the liver and spleen
Women who are planning to conceive, and who have not been vaccinated and are not immune due to having previously had the disease, should first check for the presence of anti-rubella antibodies (the test is offered free of charge in order to protect maternity) and, if need be, should be vaccinated.
Impact on the population
Rubella is endemic throughout the world and, in the absence of specific vaccination strategies, causes epidemics at intervals of 6-9 years; the age groups most affected are those from 5 to 14 years of age. The most significant peaks of incidence occur in the spring months (March-May). In Europe and North America, women of child-bearing age possess antibodies in percentages varying from 80 to 90%, depending on where they live and the time elapsed since the previous epidemic waves.
In Italy, there was an epidemic peak in 1997 with 34,612 reported cases and another peak of 6,224 cases in 2002; subsequently, in 2007, 522 cases were reported.
Regarding congenital rubella syndrome, if the disease is contracted in the first 3-4 months of pregnancy there is an increase in miscarriage and premature births. Among the live births, malformations occur in 50% of cases if contracted in the first month of pregnancy, in 22-25% if caught during the second month, in 6-15% if caught during the third month, and in 0.1% of cases if contracted during the fourth month. From the fifth month onwards the risk is minimal. In the absence of vaccination, the risk is globally estimated at 430 cases per 1,000 live births in periods of epidemics and less than 0.5 cases per 1,000 in endemic periods.
Sources / Bibliography
- Primi casi di infezione da rosolia in gravidanza notificati in Italia M Ciofi degli Atti, A Filia1, R Verteramo1, S Iannazzo2, F Curtale3, L Masini4, M De Santis4, MG Pompa
- Pediatria ANNO VI SUPPLEMENTO 2/2011 ISSN 1 9 7 0 - 8 1 6 5 Mattioli
- SURVEILLANCE REPORT Measles and rubella monitoring November 2012
- Epidemiology and Prevention of Vaccine-Preventable Diseases, The Pink Book: Course Textbook, 12th Edition Second Printing (May 2012)
- Davidkin, H Peltola and P Leinikki Epidemiology of rubella in Finland Eurosurveillance 2004;9:9-10
- S Glismann Rubella in Denmark Eurosurveillance 2004;9:9-10
- Igiene Epidemiologia Sanità Pubblica 2011; 493-497 C. Signorelli
- Ministero della salute