Rotavirus A in Brazil: Molecular Epidemiology and Surveillance during 2018–2019

Abstract

Rotavirus A (RVA) vaccines succeeded in lowering the burden of acute gastroenteritis (AGE) worldwide, especially preventing severe disease and mortality. In 2019, Brazil completed 13 years of RVA vaccine implementation (Rotarix™) within the National Immunization Program (NIP), and as reported elsewhere, the use of Rotarix™ in the country has reduced childhood mortality and morbidity due to AGE. Even though both marketed vaccines are widely distributed, the surveillance of RVA causing AGE and the monitoring of circulating genotypes are important tools to keep tracking the epidemiological scenario and vaccines impact. Thus, our study investigated RVA epidemiological features, viral load and G and P genotypes circulation in children and adults presenting AGE symptoms in eleven states from three out of five regions in Brazil. By using TaqMan®-based one-step RT-qPCR, we investigated a total of 1536 stool samples collected from symptomatic inpatients, emergency department visits and outpatients from January 2018 to December 2019. G and P genotypes of RVA-positive samples were genetically characterized by multiplex RT-PCR or by nearly complete fragment sequencing. We detected RVA in 12% of samples, 10.5% in 2018 and 13.7% in 2019. A marked winter/spring seasonality was observed, especially in Southern Brazil. The most affected age group was children aged >24–60 months, with a positivity rate of 18.8% (p < 0.05). Evaluating shedding, we found a statistically lower RVA viral load in stool samples collected from children aged up to six months compared to the other age groups (p < 0.05). The genotype G3P[8] was the most prevalent during the two years (83.7% in 2018 and 65.5% in 2019), and nucleotide sequencing of some strains demonstrated that they belonged to the emergent equine-like G3P[8] genotype. The dominance of an emergent genotype causing AGE reinforces the need for continuous epidemiological surveillance to assess the impact of mass RVA immunization as well as to monitor the emergence of novel genotypes.

Rotaviruses and Rotavirus Vaccines

“…An increase in genotype diversity was also observed in the vaccine era, with the equine-like G3P [8] variant detected in Ireland [27]. The equine-like G3P [8] variant was also reported by Gutierrez et al, where it was the dominant genotype observed in Brazil in 2018 and 2019 [28]. This study also reported a significantly higher positivity rate among children aged >24-60 months compared to other age groups [28].…”

Comparative Analysis of G1P[8] Rotaviruses Identified Prior to Vaccine Implementation in Pakistan With Rotarix™ and RotaTeq™ Vaccine Strains

“…Till now, 36 genotypes of G and 51 P have been reported worldwide (9). The epidemiological studies indicate that at least six human RVA genotypes G1P [8], G2P [4], G3P [8], G4P [8], G9P [8], and G12P [8] are globally prevalent in human infections (10).…”

An Emergence of Equine-Like G3P[8] Rotaviruses Associated with Acute Gastroenteritis in Hospitalized Children in Thailand, 2016 −2018

“…The second-round semi-nested multiplex PCR was performed using G-type-specific primers: G1-G4, G9, and G12; and P-type-specific primers: P [4], P [6], and P [8] [27−29]. For untypable samples, multiplexed one-step genotyping method with new G-and P-target specific primers was performed to identify G1−G4, G9, and G12; and P [4], P [6], P [8], P [9], and P[10] [30]. For those samples that still remained untyped were subjected to nucleotide sequencing.…”