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Istituto Superiore di Sanità - EpiCentro


The Measles Experience in 2002: The Situation in Emilia-Romagna

Luisella Grandori, Pietro Ragni, Alba Carola Finarelli, Alessia Furini, and Pierluigi Macini

Public Health Service, Health and Social Services Office, Emilia-Romagna Region

 

The Emilia-Romagna region in northeast Italy has one of the highest measles vaccine coverage rates in the country. Indeed, since 1994, coverage has exceeded 80% and in 2000 was 90% (Figure). These levels have been attained as a result of a series of complimentary activities: measles vaccine has been offered free of charge during the second year of life since 1986, and between the end of the 1980s and the early 1990s, some local health authorities conducted special vaccine campaigns designed to vaccinate the susceptible pool of previously older children who had not been previously vaccinated. Subsequently, such vaccination was routinely conducted in the remaining areas of the region during routine vaccination visits. In addition, at the end of the 1990s, a second dose was provided at 5-6 years or 11-12 years of age.

 

Until 1992, the regional incidence of measles based on mandatory reporting was similar to that of the rest of Italy, with epidemics occurring regularly at 3-year intervals (Figure).  Since 1993, however, the regional incidence has remained below the Italian average, with rates lower than 35 cases per 100,000 between 1993 and 1997 and below 2 per 100,000 from 1998 on. From the mid- 1990s, there has also been a progressive increase in the age of measles cases, which has risen from a mean of 8 years for the period 1984-1989 to 14 years during 1990-1996.

 

In 2002, the number of measles cases increased for the first time since 1997. In this article, we describe trend between January and July 2002 as well as information on regional pediatric vaccine coverage for measles.

 

The information on measles cases for this analysis are from mandatory reporting data; a review of the measles surveillance system in the pediatric age group has in fact demonstrated that in northern Italy, the sensitivity of the monthly mandatory notification system is high. In Emilia-Romagna, the reports are sent monthly from the local health agencies to the region. However, in this case, a special system with weekly reporting was put in place because of prior alerts about the epidemic occurring in the Campania region of southern Italy. Vaccination data were obtained from the local health authorities, who transmit each year the number of children vaccinated for measles by age group. In particular, since 1996, two age groups have been taken into consideration (children 24 months of age and adolescents of 13 years of age) for which data are transmitted on the number of children having received at least one dose, independent of the age at vaccine administration. Coverage was calculated using as a denominator the resident population of that age group.

 

Between January and June 2002, 209 cases of measles were reported, with a peak during the month of May (73 cases). The incidence in the general population was 5 cases per 100,000; most occurred in children between 0 and 14 years of age (131/204; 64%), with an incidence in this age group of 28 cases/100,000. The highest attack rate occurred in those between 5 and 9 years of age (51 cases reported, yielding a rate of 33/100,000). All of the local health agencies of the region notified cases, with rates ranging between 2 and 13 cases per 1000,000 Table). Of the 121 cases for which data were available on vaccine status, 16 (13%) had received at least one dose. No deaths occurred.

 

The analysis of vaccine coverage demonstrated that between 1986 and 2000, the proportion of vaccinated children at 24 months of age rose from 83% to 90%, and increased from 65% to 85% at 13 years of age. With respect to coverage by individual local health authority, in 2000 the coverage ranged from 75% to 97% at 24 months and from 72% to 92% at 13 years (Table).

 

The trends in measles in Emilia-Romagna show a progressive reduction in cases at the end of the 1980s, such that by 1999, there were a limited number of cases. It is clear that this phenomenon was closely correlated with the constant increase in vaccination coverage, which reached high levels by 2000, even though the levels remained insufficient to eliminate spread. In 2002, the number of cases increased 7-fold over levels observed in the three previous years, although the case rates in the 0-14 year age group were 80 times lower than those observed in the Campania region (2). Data collection on the 2002 cases is still ongoing, but preliminary analysis suggests that most of the cases were imported and that the high levels of coverage in the region limited secondary spread. The distribution of cases by age also reflect that expected in a highly vaccinated population; in the absence of vaccination, 90% of the cases would be expected to occur in children. There is no doubt that this is due largely to the effective barrier created by the high number of persons vaccinated over the years; the first vaccination campaigns were conducted in the 1980s. Had we had an epidemic of the dimensions observed in the pre-vaccine era, we would estimate that there would have been no fewer than 10,000 cases of measles, 500 cases of pneumonia, 10 cases of encephalitis and between 5 and 10 deaths.

 

Our findings confirm the major reductions in disease incidence achievable through vaccination. The results in Emilia-Romagna were obtained as a result of coordinated efforts involving public health districts, the local health agencies, the regional authorities as well as the pediatric community. Despite the high levels of coverage achieved, however, it will be necessary to remain vigilant and continue to ensure high vaccine coverage levels though both routine and catch-up vaccination in infants as well as older children, as has been recommended many times by experts in the field. As has been noted, the accumulation in time of susceptibles can result in epidemics even in the presence of seemingly high levels of vaccine coverage.

 

References

 

1.  Ciofi degli Atti,ML, S Salmaso, A Bella, R Arigliani, M Gangemi, G Brusoni, A E Tozzi, SPES-Study Group, Paediatric sentinel surveillance of vaccine-preventable diseases in Italy: Pediatric Infectious Disease Journal. 2002

2.  Ciofi degli Atti,ML, S Salmaso, R Pizzuti, P D'Agnese, C Bove, D Protano, A D'Argenzio, M L Trabucco, 2002, Epidemic measles in the Campania region of Italy, leads to 13 cases of encephalitis and 3 deaths: Eurosurveillance Weekly, v. 26.

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