Acute diarrhoea in a community cohort of children who received an oral rotavirus vaccine in Northeast Brazil

Abstract

Rotavirus is an important cause of childhood diarrhoea. A monovalent rotavirus vaccine (Rotarix ® ) was introduced into the Immunization Program of Brazil in 2006. In this study, we describe the incidence and burden of disease of rotavirus diarrhoea in two cohorts of children (vaccinated and unvaccinated). We followed two groups of 250 children under one year old, who were enrolled in December 2006 from a low-income residential area inNortheast Brazil. The children were monitored every two weeks for two years. Stool samples from children with diarrhoea were examined for the presence of rotavirus. Rotaviruses were genotyped using real time-polymerase chain reaction. The mean numbers of all-cause diarrhoea episodes/child (adjusted for age) in the first year were 0. 87 and 0.84, in vaccinated and unvaccinated children, respectively. During the second year, the number of episodes/ child decreased to 0.52 and 0.42. Only 16 (4.9%) of 330 stool samples were rotavirus-positive (10 vaccinated and 6 unvaccinated children) and only P[4]G2 rotaviruses were identified. All-cause diarrhoea episodes were more severe in unvaccinated children in the first year of age (p < 0.05), while vaccinated children had more severe episodes 18 months after vaccination. Rotavirus diarrhoea incidence was very low in both groups. Key words: diarrhoea -rotavirus -vaccine -cohort -children -BrazilRotavirus diarrhoea in vaccinated children • Sarah Cristina Fontes Vieira et al. 331ties were visited at home in 2006 and their parents were invited to enrol their children in the study, independent of their vaccination status. The parents of the first 250 children who had received two oral doses of the Rotarix ® vaccine (GlaxoSmithKline Biologicals, Rixensart, Belgium) at two and four months of age (vaccinated cohort) were invited to participate and a further 250 children who had not received the vaccine comprised the unvaccinated cohort. Vaccination status was verified using the child's vaccination card and the Health Centre's databases. The youngest unvaccinated children registered were selected, despite the fact that the two groups could not be matched by age, as unvaccinated children had to be ineligible for vaccination at the time of enrolment, and therefore at least four months of age. Unvaccinated children serving as the control group were not offered the vaccine due to EPI guidelines that exclude children greater than or e�ual to four months of age to avoid the risk of intussusception among older infants (WHO 2007).After obtaining informed parental consent, all children were visited at home for the following two years, independently of their age at the time of enrolment. Visits were conducted every two weeks by three trained interviewers who in�uired as to whether or not the child had experienced diarrhoea episodes during the previous twoweek period. If the parent indicated that the child had diarrhoea, the interviewer collected information regarding the date of the episode and clinical presentation. The severity of the diarrhoea episodes wa...

Diarrhea incidence and intestinal infections among rotavirus vaccinated infants from a poor area in Brazil: a spatial analysis

“…The number of acute diarrhea episodes/child/year was low and very few children had rotavirus diarrhea detected. These findings are similar to the ones found by Vieira et al (2011) [20], that in an urban district of Aracaju city detected 0.87/episodes/child/year and 3.0% rotavirus associated diarrhea.…”

Incidence of Acute Diarrhea Among Children Aged 0 - 1 Year in Southern Brazil, 2012

“…A cohort study in Northeast Brazil followed up 250 children under 1 year of age for 2 years. In the first year of follow-up, researchers found an incidence rate less significant than that observed in this study (8.4 and 8.7 cases of diarrhea per 1,000 children vaccinated and not vaccinated against rotavirus, respectively) (13).…”

Population effectiveness of the pentavalent and monovalent rotavirus vaccines: a systematic review and meta-analysis of observational studies

“…Five studies included community consultations for either RVGE or AGE [ 17 – 21 ], which included a range of definitions including outpatient attendance, physician consultation and telephone consultation. The study by Fontes Vieira et al 2011 conducted in Brazil on a community cohort examined effectiveness of vaccination against laboratory confirmed RVGE but did not report an estimate of VE; a crude estimate was therefore calculated by the authors [ 17 ]. In the majority of studies, laboratory confirmation of RVGE followed hospitalisation, an ED attendance or GP consultation for gastroenteritis symptoms such as diarrhoea.…”

“…The majority of studies either matched controls or adjusted for age in the analysis as a minimum and those with community controls often used an indicator of residence such as GP location as a covariate. A high risk of bias was identified in two out of seven cohort studies [ 17 , 23 ] and two out of 23 case-control studies had a high risk of bias [ 24 , 25 ].…”

“…A single study reported full dose vaccine effectiveness against community consultations for laboratory confirmed RVGE, reporting a high unadjusted VE estimate of 96% (95% CI 76-100%) [ 20 , 21 ]. However, four cohort studies included estimates of vaccine effectiveness for community consultations for AGE [ 17 – 21 ]. Three studies were from high income countries and one from middle-income.…”