Rotavirus vaccination in Brazil: effectiveness and health impact seven years post-introduction

Abstract

Before vaccine introduction in Brazil, rotavirus caused approximately 650,000 outpatient visits, 92,000 hospitalizations and 850 deaths annually among children aged <5 years. Brazil was one of the first countries to introduce rotavirus vaccination into the National Immunisation Program (NIP), in 2006, but estimated coverage (87.1%) for 2011 remained lower if compared with other routine immunizations (95%). Case–control studies reached effectiveness rates as high as 85%. Observational studies showed a significant reduction in gastroenteritis-related hospitalizations and deaths among children aged <1 year, at rates as high as 48 and 54%, respectively. There was a significant increase in the relative prevalence of G2P[4] genotype after vaccine introduction, reaching 100% of strains in some settings. A small increase in intussusception incidence was seen within 1 week following the second vaccine dose, but benefits far outweigh any potential risk. This article provides an in-depth review of postlicensure studies conducted in Brazil 7-year postintroduction.

Keywords::

• Brazil
• effectiveness
• gastroenteritis
• genotypes
• intussusception
• rotavirus
• vaccine impact
• vaccines

Financial & competing interest disclosure

AC Linhares was the principal investigator of studies with the Human Rotavirus Vaccine (Rotarix^®) in Belém, Brazil, and MCA Justino was the clinical coordinator of these studies. Both investigators are affiliated to Instituto Evandro Chagas, Health Surveillance Secretariat, Brazilian Ministry of Health, which received research funding from GlaxoSmithKline Biologicals. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript, apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Prior to the introduction of rotavirus vaccination in Brazil, rotavirus disease burden was translated into approximately 3.5 million gastroenteritis (GE) episodes, more than 650,000 outpatient visits, more than 92,000 hospitalizations and 850 deaths annually in children under 5 years of age.

• Brazil was among the first countries in Latin America to introduce rotavirus vaccination into the National Immunisation Program (NIP) in March 2006. Among the several factors that have played a key role in the decision of implementing rotavirus vaccination in Brazil, it should be emphasized that the Ministry of Health’s political decision, the availability of epidemiological data and a cold-chain storage capacity were available.

• Since its introduction in Brazil in 2006, rotavirus vaccine uptake increased progressively, although at different levels across the regions. In 2011, administrative coverage for rotavirus vaccine ranged from 72 to 93% in the Northern and South-Eastern regions, respectively. As compared to other routine immunizations (e.g., DTP-Hib), rotavirus vaccine coverage remains consistently lower over time.

• The rotavirus vaccine effectiveness under programmatic use in Brazil was evaluated in two case–control studies. Overall, a significant protection was achieved against severe rotavirus GE, ranging from 76 to 85% in the Northern and North-Eastern regions.

• Several ecological, observational studies in Brazil have shown a significant impact of rotavirus vaccination on morbidity and mortality all over Brazil. After introduction of rotavirus vaccination into the NIP, there was a substantial reduction in all-cause GE-related hospitalizations and deaths among children aged <1 year, and a significant decrease was observed in hospitalizations due to rotavirs in São Paulo.

• There was an increase in the prevalence of G2P[4] rotavirus strains following the implementation of rotavirus vaccine into the Brazilian NIP in 2006. Whether this could be a vaccine-induced change or merely reflects a natural fluctuation over time remains to be determined. In more recent years, there appears to occur a trend for continuous decrease in the prevalence of G2P[4].

• One postlicensure study conducted in Brazil has shown a small, albeit significant increased risk of intussusception within 1 week postsecond rotavirus vaccine dose (incidence rate: 2.6 [95% CI: 1.3–5.2]). Unlike in other countries (e.g., Mexico), there was no small clustering of intussusception following the first dose.

Notes