Versione italiana

 BEN - Notiziario ISS - Vol.15 - n.11

An Epidemic of Measles in Ascoli Piceno (Marche Region)

Andrea Filonzi¹, Mirea DeSantis¹, Maria Gabrielli¹, Roberta Girardo¹, Giancarlo Viviani², and Barbara Airini²

¹Health and Hygiene Service Local Health Authority 13, Ascoli Piceno

²University of Ancona; School of Specialization in Hygiene and Preventive Medicine

Measles is a highly contagious infectious disease. In 2002, a major epidemic occurred in Southern Italy. The most heavily affected region was Campania, with more than 10,000 cases reported. In the Marche Region of Central Italy, 19 cases were notified in April of 2002, compared with only 8 cases reported during all of 2001 (1).

In 1986, the Marche Region in collaboration with the ISS, has promoted extensive programs of measles vaccination who have lead to a progressive increase in vaccination coverage, reaching a mean regional coverage in 1999 of 82%. In Local Health Authority 13 of Ascoli Piceno, that covers a population of 117, 427 residents, the vaccination coverage in 2002 was 96% for the 1999 birth cohort; measles coverage measured in 2001 among adolescents at age 12 years was 93%.

The last measles epidemic in  the Local Health Authority 13 of Ascoli Piceno occurred in 1997, when there were 70 cases of measles. No cases were notified in either 2002 or 2001, but between June and early July of 2002, 27 cases were reported.

Fore each of the 27 notified cases, an epidemiologic investigation was conducted to determine whether each met the case definition and to determine, where possible, the chain of transmission, “investigating back in time to ultimately discover the external source of the infection and forward in time to determine whether it is possible to interrupt the chain of transmission through immunization and other means of prophylaxis” (2).

The onset of symptoms in the first notified cased occurred at the beginning of June; the last case occurred in early July. The peak of the epidemic curve occurred during the second and third weeks of June.

Of the 27 cases, 14 were female. Their mean age was 12.7 years (range 1-37). Cases were reported from the city of Ascoli Piceno, in 3 other communes, and in 5 rural areas, but 13 of the 27 cases (48%) came from the single commune of Offida. Five of the cases had been vaccinated (3 in 1991, one in 2000, and the remaining case just 10 days before onset of symptoms.

Of the 13 cases from Offida, 11 attended the local elementary school (Figure). The school has 235 students; the attack rate was therefore 4.7%. Vaccine coverage among the students was 80.9% (190/325). None of those who developed measles had been vaccinated, while 11 of 45 (24.5%) of the non-vaccinated children became ill. Vaccine efficacy in this school setting was therefore 100%.

Of the 27 total cases reported in the local health authority, 25 were Italians; all were residents of the area. The two non-Italian cases were 9 and 11 year old brothers from Kosovo who had not been vaccinated and who had recently visited relatives in the Campania region, the area of Italy most affected by the epidemic. Both developed illness during the first week of June, and the nine year old was the first case to occur in the elementary school in Offida.

The high vaccine coverage in the students in the Offida elementary school appears to have limited the spread of the epidemic, but in was not adequate to prevent spread among unvaccinated students. In fact, nearly a quarter of the non-vaccinated became ill.

In Local Health Authority 13 of Ascoli Piceno, the overall high coverage did not prevent the appearance of this small outbreak. In terms of public health, the importance of these unvaccinated individuals depends on their geographic distribution in “pockets” of susceptibility that can sustain transmission. It also underlines the importance of vaccinating immigrants or other new arrivals to the area who have not been vaccinated or whose vaccine status is unknown.

The strategy used to control the epidemic consisted of identification of contacts of cases and obtaining lists of school students and summer church and recreational groups in order to actively vaccinate the susceptibles. Vaccination was facilitated by the intense national and local press and media coverage given to the epidemic in Italy and by the collaboration between the Department of Prevention and the pediatricians and general practitioners of the area.

References

1. Servizio Sanità Regione Marche. Circolare n. 10398 del 6 Giugno 2002: “Epidemia di morbillo in Italia. Controllo della diffusione e vaccinazione dei contatti”

2. Ministero della Sanità. Circolare n. 12 del 13 Luglio 1999: “Controllo ed eliminazione di morbillo, rosolia e parotite attraverso la vaccinazione”

3. Regione Marche. Delibera della Giunta n. 3072 del 13.11.1995: “Prevenzione delle malattie infettive – obiettivo: eliminazione del morbillo e della Rosolia congenita”