Impact of universal varicella vaccination of one year-olds in Uruguay: 1997-2005
Jorge Quian 1, Ricardo Rüttimann 2, Claudia Romero 1, Patricia Dall'Orso 1, Alfredo Cerisola 3, Thomas Breuer 4, Michael Greenberg 4* and Thomas Verstraeten 4
1 Pediatric Department, Republic University, Montevideo, Uruguay
2 GlaxoSmithKline Biologicals, Buenos Aires, Argentina
3 Pediatric Clinic, Republic University, Montevideo, Uruguay
4 GlaxoSmithKline Biologicals, Rixensart, Belgium
* To whom correspondence should be addressed. E-mail: michael.greenberg{at}gskbio.com.
Accepted 11 April 2008
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Objective: Varicella vaccination was introduced at the end of 1999 into the Uruguayan immunisation schedule for children 12 months of age. VarilrixTM (Oka strain; GlaxoSmithKline Biologicals) has been the only vaccine used since then and coverage has been estimated to exceed 90% since the start of the universal varicella vaccination program. We assessed the impact of the Uruguayan varicella vaccination program through 2005, six years after its introduction.
Methods: Information on hospitalisations was collected from the main paediatric referral hospital and information on medical consultations for varicella was collected from two private health insurance systems in Montevideo. The proportion of hospitalisations due to varicella and proportion of ambulatory visits for varicella since introduction of the vaccine were compared between 1999-2005 and 1997-1999 in the following age groups: < 1 year, 1-4 years, 5-9 years and 10-14 years.
Results: By 2005, the proportion of hospitalisations due to varicella among children was reduced by 81% overall and by 63%, 94%, 73%, and 62% in the < 1, 1-4, 5-9 and 10-14 years age groups, respectively. The incidence of ambulatory visits for varicella among children was reduced by 87% overall and by 80%, 97%, 81%, and 65% in the < 1, 1-4, 5-9 and 10-14 years age groups, respectively.
Conclusions: The burden of varicella has decreased substantially in Uruguayan children since the introduction of varicella vaccination, including those groups outside the recommended vaccination age. It is expected to decrease further as more cohorts of children are vaccinated and herd immunity increases.
