Eurosurveillance - Volume 9, Issue 4, 01 April 2004

The current issue of Eurosurveillance provides the common theme of the epidemiology and control of congenital rubella infection (CRI) across Europe. It provides a stark reminder that despite the availability of a safe and effective vaccine for many years, CRI - the consequence of rubella infection during pregnancy, remains an important public health problem both in the European Union and the wider WHO European Region. The following articles outline the various operational challenges facing national immunisation programmes in Europe. They vividly illustrate large differences in disease burden and inequalities in access to preventive health services both between and within countries. Four groups of countries can be distinguished.

The World Health Organisation (WHO) Regional Office for Europe has recently published a strategic plan and surveillance guidelines for measles and congenital rubella infection. The strategy prioritises measles control activities but encourages the introduction of rubella vaccine when measles vaccine coverage has reached >90 %; although, many western European countries with suboptimal measles vaccine coverage are already using the combined measles, mumps and rubella (MMR) vaccine. Women in these countries may have an especially high risk of having an infant with congenital rubella syndrome. WHO is seeking to improve the surveillance for rubella and congenital rubella syndrome as a means to obtain better information on the burden of these diseases and engage policy decision makers in the need to support the WHO European Region's strategies for rubella.

Serological surveillance is an important resource to evaluate vaccine programmes, especially for diseases such as rubella, where a sub-optimal programme can lead to an increase in morbidity. A coordinated vaccine policy in Europe is needed and the aim of the European Sero-Epidemiology Network (ESEN2) is to standardise serological surveillance in 22 countries for eight diseases, including rubella.

Romania experienced a large rubella outbreak in 2002-03, with more than 115 000 reported cases nationwide, and an incidence of 531 reported cases per 100 000 population. The incidence was highest in children of school age. The cohorts of adolescent girls vaccinated in 1998 and 2002 (when a rubella-containing vaccine was available) had significantly lower incidence rates (p<0.001) compared with those in boys in the same age groups who were not vaccinated. In 2003, of the 150 suspected congenital rubella syndrome (CRS) cases reported, seven (4.6%) were confirmed by positive rubella IgM antibodies. In the absence of available rubella containing vaccine for outbreak control, an outbreak response plan to improve the detection of cases and to limit rubella virus transmission was developed. The following activities were conducted: surveillance of pregnant women with suspected rubella or history of exposure to rubella virus was implemented, with follow up of pregnancy outcomes; surveillance for CRS was strengthened; existing infection control guidelines to prevent disease transmission within healthcare facilities were reinforced; and a communication plan was developed. In May 2004, Romania is introducing measles, mumps and rubella (MMR) vaccine for routine vaccination of children aged 12 to 15 months, while continuing vaccination of girls in the 8th grade of school (13-14 years of age) with rubella-only vaccine.

An average of 20 000 rubella cases were recorded annually in Denmark until 1987. In 1989, however, only 1006 cases were reported, and the true current incidence of rubella infection in Denmark is unknown but considered to be very low and <1 per 100 000 population. The significant decrease in the inci-dence of rubella mirrors the success of vaccination of rubella seronegative women of childbearing age, which was initiated in Denmark in 1980. From 1982 and onwards the national health security scheme also refunded vaccina-tion of children and the MMR vaccine was introduced in the Danish child-hood vaccination program in 1987. The low incidence has been sustainable due to these interventions, and since 1994 congenital rubella syndrome and rubella in pregnancy have been listed as notifiable infectious diseases in Denmark. Nevertheless, in order to meet the WHO goal of control of rubella in the Region, the introduction of mandatory reporting of all laboratory diagnosed rubella cases is now being considered.

Before rubella vaccination programmes began, rubella infection was prevalent in Finnish children. The disease occurred as epidemics at intervals of a few years. Rubella infection was most often contracted between the ages of 2 and 12 years. Vaccinations specifically aimed at eradicating rubella were begun with monocomponent vaccine in the mid-1970s, and the measles, mumps and rubella (MMR) vaccination programme with two injections got underway in 1982. A clear reduction in rubella cases was evident a few years after the launch of the MMR programme. Owing to a sufficiently high vaccination coverage (>95% since 1987), circulation of the indigenous rubella virus in the Finnish population ceased in the late 1990s. Some rubella cases have been imported to Finland since elimination, but they have not caused any secondary cases. This shows unambiguously that protection against rubella continues to be effective, although our cohort studies imply that the vaccine induced antibody levels do decrease with time. The MMR programme has also eliminated congenital rubella syndrome (CRS) from the country. The last CRS case was recorded in 1986. As a result of the high coverage two dose MMR vaccination programme, rubella was successfully eliminated from Finland. How long the acquired protection will last remains to be seen.

In the pre-vaccination era, rubella was regarded as only a mild exanthematous acute viral infection of children. The devastating effects of the disease were first identified in the early 1940s by an Australian ophthalmologist, and further confirmed during the 1962-65 rubella pandemic in Europe and the United States. They result from the transmission of the virus by infected pregnant women to their fetus. The resulting congenital rubella syndrome (CRS) comprises a lengthy list of abnormalities. The most common ones are deafness, ocular and cardiac defects and mental retardation. The objective of rubella vaccination, to which France has subscribed, is the elimination of CRS [1].

In 1993, there was a large epidemic of rubella and congenital rubella syndrome (CRS) in Greece. The epidemiology of rubella and CRS after 1993 is described in this paper using information from surveillance data and published studies and reports. The incidence of rubella fell sharply after 1993, but a smaller outbreak occurred in 1999, mainly in young adults, and four CRS cases (4.0 per 100 000 live births) were recorded. A very high proportion of the child population in Greece are currently vaccinated for rubella, while teenagers are inadequately covered (60-80% in different studies). A substantial proportion of women of childbearing age are susceptible to rubella (10-20% in urban areas). This could lead to local or more extended outbreaks. This situation shows that a comprehensive preventive policy should be implemented.

In Italy, rubella vaccination has been recommended since 1972 for pre-adolescent girls, and since the early 1990s for all children in the second year of life. Nevertheless, coverage in children from 12 to 24 months of age is suboptimal (i.e., 56% in 1998, 78% in 2003), with wide variations among regions. As a result, rubella is still circulating in Italy, and in 1996 the percentage of women susceptible to rubella between 15 and 39 years of age was >5%. Congenital rubella syndrome (CRS) was a notifiable disease between 1987 and 1991, with a range of 8-76 cases reported annually. Since 1992, national incidence data are no longer available, but local reports show that CRS cases are still occurring. Nationwide, coordinated and uniform actions are needed to control CRS effectively. For this reason, the National Plan for the Elimination of Measles and of Congenital Rubella has recently been launched. This plan includes strategies aimed at increasing MMR vaccination coverage in children and specific control measures for congenital rubella control, i.e., improving the vaccination of susceptible women of childbearing age, and reintroducing national surveillance of CRS.

In most of western Europe the rubella vaccine coverage is high. However, prior to the introduction of the vaccine in Latin America, rubella susceptibility in women of childbearing age was 10-25%. Forty one (93%) countries in Latin America have adopted the rubella vaccine since 2002. The adult immigrant population in Spain constitutes a group of susceptibles. In February 2003, the Madrid Community Measles Elimination Plan detected an increase in rubella notifications in women who had been born in Latin America. A descriptive study was undertaken to characterise the outbreak. A confirmed case was a person with fever or rash and a positive IgM serology, and living in Madrid, between 1 December 2002 and 31 March 2003. The secondary attack rate (SAR) per household was calculated. A total of 19 cases of rubella were identified, 15 were confirmed and 4 were probable cases. Fourteen (73.7%) cases were women at childbearing age. The mean age was 25.1 years. One pregnancy was diagnosed with a voluntary termination. Eleven (57.9%) cases were from Ecuador. The mean time of residence in Spain was 41 months. None of the cases or the 54 (78.3%) household contacts had been vaccinated against rubella. The SAR was 9.1%. This study showed the spread of rubella in the susceptible Latin American Community that is resident in Madrid. The interventions proposed were a vaccination programme towards immigrants, a health education campaign to prevent congenital rubella, and a health professional training programme case management.

Rubella vaccine was offered to schoolgirls in the United Kingdom (UK) from 1970, with antenatal testing and postpartum vaccination for susceptible women introduced during the 1970s. Mass vaccination with MMR of children aged 12-15 months was introduced in 1988; schoolgirl vaccination was discontinued in 1996 and replaced by a second dose of MMR for pre-school children; postpartum vaccination of susceptible women identified through antenatal testing continues. Rubella was made a notifiable disease in 1988, and is monitored through clinical and laboratory reports; data are available on rubella associated terminations and congenital rubella syndrome(CRS) births, rubella susceptibility in population subgroups, and vaccine uptake. Reported cases of CRS declined from about 50 a year 1971-75 to just over 20 a year 1986-90, and rubella associated terminations from an average of 750 to 50 a year. About 40 infants with CRS have been reported since 1991; about a third of their mothers were infected abroad, most in their country of origin (imported infections), a third were born abroad but acquired infection in the UK, and a third were UK-born. Women living in the UK who were born abroad have much higher rubella susceptibility rates than UK-born women. Although there is currently very little rubella infection circulating, uptake of MMR has dropped by over 10% since 1995. If rubella starts to circulate again, immigrant women will be at increased risk of acquiring infection in pregnancy.