Hospital-based surveillance to evaluate the impact of rotavirus vaccination in São Paulo, Brazil.
BACKGROUND
Brazil implemented routine immunization with the human rotavirus vaccine, Rotarix, in 2006 and vaccination coverage reached 81% in 2008 in São Paulo. Our aim was to assess the impact of immunization on the incidence of severe rotavirus acute gastroenteritis (AGE).


METHODS
We performed a 5-year (2004-2008) prospective surveillance at a sentinel hospital in São Paulo, with routine testing for rotavirus in all children less than 5 years of age hospitalized with AGE. Genotypes of positive samples were determined by reverse transcription polymerase chain reaction.


RESULTS
During the study, 655 children hospitalized with AGE were enrolled; of whom 169 (25.8%) were positive for rotavirus. In the postvaccine period, a 59% reduction in the number of hospitalizations of rotavirus AGE and a 42.2% (95% confidence interval [CI], 18.6%-59.0%; P = 0.001) reduction in the proportion of rotavirus-positive results among children younger than 5 years were observed, with the greatest decline among infants (69.2%; 95% CI, 24.7%-87.4%; P = 0.004). Furthermore, the number of all-cause hospitalizations for AGE was reduced by 29% among children aged <5 years. The onset and peak incidences of rotavirus AGE occurred 3 months later in the 2007 and 2008 seasons compared with previous years. Genotype G2 accounted for 15%, 70%, and 100% of all cases identified, respectively, in 2006, 2007, and 2008.


CONCLUSIONS
After vaccine implementation, a marked decline in rotavirus AGE hospitalizations was demonstrated among children younger than 5 years of age, with the greatest reduction in the age groups targeted for vaccination. The predominance of genotype G2P[4] highlights the need of continued postlicensure surveillance studies.
Sáfadi
Marco Aurelio Palazzi
MA
Division of Pediatric Infectious Diseases, Department of Pediatrics, Santa Casa School of Medical Sciences, São Paulo, Brazil. masafadi@uol.com.br
Berezin
Eitan Naaman
EN
Munford
Veridiana
V
Almeida
Flavia Jaqueline
FJ
de Moraes
Jose Cassio
JC
Pinheiro
Cid Fernando
CF
Racz
Maria Lucia
ML
D000208:Acute Disease; D001938:Brazil / Q000453:epidemiology; D016009:Chi-Square Distribution; D002675:Child, Preschool; D005243:Feces / Q000821:virology; D005759:Gastroenteritis / Q000453:epidemiology* / Q000517:prevention & control / Q000821:virology; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D011159:Population Surveillance; D011446:Prospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012401:Rotavirus / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D012400:Rotavirus Infections / Q000453:epidemiology* / Q000517:prevention & control / Q000821:virology; D022243:Rotavirus Vaccines / Q000008:administration & dosage* / Q000276:immunology; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology
C492457:RIX4414 vaccine; D022243:Rotavirus Vaccines; D014613:Vaccines, Attenuated