Re-emergence of Measles in Young Infants

Abstract

To the Editors: The World Health Organization goal of eliminating measles in Europe will not be met by the targeted year 2010.1 In Italy measles incidence declined since vaccine introduction in 1998. Childhood vaccination coverage at 24 months has increased from 56% in 1998 to 90% in 2008.2 Although public health authorities have made extraordinary efforts, measles is still spreading throughout Europe.3 After sporadic cases or clusters nationwide during the previous years, we recently observed a local resurgence of measles.3 At Bambino Gesù Hospital, in Rome, we had no hospitalizations associated with measles from January 2009 to February 2010, whereas we admitted into hospital 26 laboratory confirmed cases from March to September 2010. The median age was of 6 years (range from 1 month to 17 years). The observed complications were dehydration in 13 cases, pneumonia in 11 cases, and otitis in 2 cases. None of them died or had disabling sequelae after discharge. Measles circulation is likely a result of suboptimal vaccination coverage, even if vaccine is offered free-of-charge in a 2-dose routine immunization program, at 12 to 15 months and at 5 to 6 years of age.4 Vaccine coverage depends strongly on the acceptance of vaccination by parents, as well as on recommendations by pediatricians. Parents are free to decide on their child's vaccinations and measles immunization is not mandatory for school admission. Parents may consider the potential profit for the community—due to herd immunity effects and a reduced economical burden—as less important than the individual risk from potential vaccination side-effects. Among our hospitalized children, 7 were too young to be vaccinated. Four children were 3 months or younger and 3 were less than 12 months of age. Only one of the mothers of these children was immunized. Four mothers developed the disease 1 week before their children and they were the likely source of infection. In 1 case, the older sister experienced measles 10 days before and probably transmitted the disease to the infant. As for the other infants, parents were not able to identify the source of infection. Immunization was delayed or not consented by the parents of the older 19 children, who then likely had been infected in the household or at school. Among the reasons for not getting vaccinated were: (a) fear of injections or of side effects; (b) perception of measles as a benign disease; (c) no need of vaccination as the child seemed to be healthy; (d) perception of measles as an eliminated disease from Europe and consequently vaccination as unnecessary. Finally, we should consider the important role of the not yet vaccinated infants who may not be protected by passive immunity or who can experience waning immunity. In fact, measles immunity transmitted by mothers may wane shortly after birth.5 In conclusion, to prevent perspective outbreaks and interrupt measles circulation, strong efforts should be made to achieve and maintain routine coverage over 95%, to adhere to the immunization schedule, to immunize susceptible adults, and to consider offering the vaccine at 9 months of age. Elena Bozzola, MD Anna Quondamcarlo, MD Andrzej Krzysztofiak, MD Laura Lancella, MD Infection Unit Ospedale Pediatrico Bambino Gesù Mariateresa Romano Epidemiology Unit Ospedale Pediatrico Bambino Gesù Alberto Tozzi, MD Epidemiology Unit Ospedale Pediatrico Bambino Gesù Rome, Italy