Effect of 10-Valent Pneumococcal Vaccine on Pneumonia among Children, Brazil

Eliane Terezinha Afonso, Ruth Minamisava, Ana Luiza Bierrenbach, Juan Jose Cortez Escalante, Airlane Pereira Alencar, Carla Magda Domingues, Otaliba Libanio Morais-Neto, Cristiana Maria Toscano, and Ana Lucia Andrade

Author affiliations: Federal University of Goiás, Goiania, Goiás, Brazil (E.T. Afonso, R. Minamisava, A.L. Bierrenbach, O.L. Morais-Neto, C.M. Toscano, A.L. Andrade); Pontifical Catholic University of Goiás, Goiania (E.T. Afonso); Ministry of Health, Brasilia, Brazil (J.J.C. Escalante, C.M. Domingues); University of Brasília, Brasília (C.M. Domingues); University of São Paulo, São Paulo, Brazil (A.P. Alencar)

Abstract

Pneumonia is most problematic for children in developing countries. In 2010, Brazil introduced a 10-valent pneumococcal conjugate vaccine (PCV10) to its National Immunization Program. To assess the vaccine’s effectiveness for preventing pneumonia, we analyzed rates of hospitalization among children 2–24 months of age who had pneumonia from all causes from January 2005 through August 2011. We used data from the National Hospitalization Information System to conduct an interrupted time-series analysis for 5 cities in Brazil that had good data quality and high PCV10 vaccination coverage. Of the 197,975 hospitalizations analyzed, 30% were for pneumonia. Significant declines in hospitalizations for pneumonia were noted in Belo Horizonte (28.7%), Curitiba (23.3%), and Recife (27.4%) but not in São Paulo and Porto Alegre. However, in the latter 2 cities, vaccination coverage was less than that in the former 3. Overall, 1 year after introduction of PCV10, hospitalizations of children for pneumonia were reduced.

Streptococcus pneumoniae infections are the leading cause of bacterial pneumonia, meningitis, and sepsis among children (1,2); in developing countries, these infections account for almost a half million deaths among children <5 a="" age="" href="http://wwwnc.cdc.gov/eid/article/19/4/12-1198_article.htm#r3" of="" title="3" years="">3
). In Brazil, the largest country in South America, the role of S. pneumoniae in pneumonia in children is considerable (4,5). Brazil is composed of 5 administrative regions with different climatic and socioeconomic characteristics. In 2010, the estimated population of infants (children <12 17="" 1="" a="" age="" and="" births="" deaths="" href="http://wwwnc.cdc.gov/eid/article/19/4/12-1198_article.htm#r6" infant="" live="" months="" mortality="" of="" per="" rate="" the="" title="6" was="">6
,7). In Brazil, the main reason for hospitalization of infants is pneumonia (6). Vaccination with pneumococcal conjugate vaccine (PCV) is a public health intervention to prevent pneumococcal disease. PCV has been in use since 2000, when a 7-valent vaccine (PCV7) was licensed in the United States for routine use in children. In 2010, PCV7 was replaced by a 13-valent vaccine. Recently, a 10-valent pneumococcal conjugate vaccine (PCV10) was licensed in Brazil; this vaccine includes the same serotypes that are in PCV7 (4, 6B, 9V, 14, 18C, 19F, 23F), plus 3 more (1, 5, and 7F) (8).
In 2010, Brazil introduced PCV10 into its routine National Immunization Program. Previously, no PCV had been incorporated into the routine immunizations. The vaccination was introduced in all cities from March through September 2010; 3 doses (at 2, 4, and 6 months of age) plus 1 booster (at 12–15 months of age) were recommended. Two routine catch-up schedules were also in place: 1) two doses for children 7–11 months of age plus a booster at 12–15 months of age, and 2) one dose for children 12–24 months of age. PCV10 is not given to children >24 months of age (9).
In Brazil, vaccination of children with PCV10 is free through the National Unified Health System (10). By October 2011, the mean vaccination coverage rapidly reached 80% for a full primary series for children <12 age="" in="" months="" of="">5,000 municipalities (Brazilian Ministry of Health, unpub. data).
Studies that assessed the effect of PCV7 found a statistically significant reduction in the overall incidence of invasive pneumococcal disease and hospitalizations for pneumonia among children <2 a="" after="" age="" first="" href="http://wwwnc.cdc.gov/eid/article/19/4/12-1198_article.htm#r11" of="" shortly="" the="" title="11" vaccination="" year="" years="">11
–14). Our aim was to assess the effectiveness of PCV10 for reducing hospitalizations for all-cause pneumonia. We analyzed trends in rates of hospitalization for pneumonia among children soon after the introduction of PCV10 in Brazil. Ethical approval was granted by the Ethics Committee, Federal University of Goiás, Goiania, Brazil.