Rotavirus Genotypes Circulating in Brazil, 2007-2012: Implications for the Vaccine Program

Abstract

SUMMARYRegarding public health in Brazil, a new scenario emerged with the establishment of universal rotavirus (RV) vaccination programs. Herein, the data from the five years of surveillance (2007-2012) of G- and P-type RV strains isolated from individuals with acute gastroenteritis in Brazil are reported. A total of 6,196 fecal specimens were investigated by ELISA and RT-PCR. RVs were detected in 19.1% (1,181/6,196). The peak of RV incidence moved from June-August to September. RV was detected less frequently (19.5%) among children ≤ 5 years than in older children and adolescents (6-18 years) (40.6%). Genotype distribution showed a different profile for each year: G2P[4] strains were most prevalent during 2007-2010, G9P[8] in 2011, and G12P[8] in 2012. Mixed infections (G1+G2P[4], G2+G3P[4]+P[8], G2+G12P[8]), unusual combinations (G1P[4], G2P[6]), and rare strains (G3P[3]) were also identified throughout the study period. Widespread vaccination may alter the RV seasonal pattern. The finding of RV disease affecting older children and adolescents after vaccine implementation has been reported worldwide. G2P[4] emergence most likely follows a global trend seemingly unrelated to vaccination, and G12, apparently, is emerging in the Brazilian population. The rapidly changing RV genotype patterns detected during this study illustrate a dynamic population of co-circulating wildtype RVs in Brazil.

Rotavirus epidemiology and surveillance before vaccine introduction in Argentina, 2012–2014

“…Interestingly, G1P[8] and G12P[8] genotypes are re‐emerging after years of circulating at low frequencies. This phenomenon is observed even in countries where massive vaccination has been implemented for nearly a decade [Kirkwood et al, ; Luchs et al, ]. Because until now estimated coverage of vaccine in the private health sector does not exceed 20% of Argentine live birth cohort [Jorge Gómez, personal communication], the emergence and variation of strains within our country seems to reflect a natural fluctuation of rotavirus.…”

Rotavirus Vaccines: a story of success with challenges ahead

“…Serotype replacement leading to an increase in non-vaccine serotypes over time, due to possible vaccine selective pressure, has been repeatedly postulated during the past decade, but it lacks robust supporting evidence. Increases in the predominance of specific rotavirus serotypes, heterotypic to the vaccines in use, have occurred, but mostly in a temporal manner similar to the known unpredictable regional and temporal variability of rotavirus serotype circulation observed before the vaccine era 7 , 63 . The biological plausibility of a selective pressure phenomenon is low, as rotavirus vaccines do not abolish the circulation of any particular serotype (protection against infection does not surpass 60%) and “competition” between different serotypes within the intestine (as occurs for pneumococcus in the nasopharynx) is unlikely.…”

Group A rotavirus gastroenteritis: post-vaccine era, genotypes and zoonotic transmission

“…Some authors suggested this prevalence would be associated to vaccine pressure, and the introduction of a monovalent G1P[8] vaccine could have created conditions for the G2P[4] strain acquiring advantages over the other strains (that share the P[8] genotype) when competing for infection of susceptible hosts. ( 33 , 55 ) However, other common (G1P[8], G3P[8] or G9P[8]) strains continued to circulate marginally along time, ( 33 ) as observed in surveillance of RVA strains in Australia. ( 56 ) The emergence of G2P[4], in 2007, was also reported in countries that introduced the pentavalent vaccine Rotateq ® in their vaccine calendars, like Australia and Nicaragua, ( 56 , 57 ) and in non-vaccinated populations (such as in Portugal, Argentine and Paraguay).…”

“…RotaTeq ® is also licensed in the country but it is available only in private vaccination services. ( 33 )…”

“…The United States, Belgium and Brazil demonstrated a delay of one to two months in beginning of RVA infection season after introducing the vaccine. ( 33 , 46 , 47 ) The indirect benefits and/or losses caused by RVA vaccination should be further analyzed.…”