Convalescent phase sera from children infected with G12 rotavirus cross-neutralize rotavirus strains belonging to the Wa genogroup.

The emergence of G12 rotaviruses raises questions about the ability of candidate vaccines in providing protection against such emerging genotypes. Therefore, we assessed cross-neutralization against four reference rotavirus strains namely Wa (G1P[8]), DS-1 (G2P[4]), 116E (G9P[11]) and RV024 (G12P[6]) using paired sera from 28 children infected with G1P[8], G2P[4], G9P[6/8] or G12P[6] genotypes. Convalescent sera of G12P[6]-infected children demonstrated heterotypic response against 116E and Wa strains (50 and 33.3 %). In contrast, none of the four G2P[4]-infected children seroconverted against Wa or RV024 rotaviruses. The geometric mean neutralizing antibody titre in convalescent sera of G12P[6]-infected children was eightfold higher against strains belonging to the Wa genogroup (i.e. G1, G9 and G12 rotavirus) than against strains belonging to the DS-1 genogroup (G2 rotavirus). In conclusion, this study demonstrates that neutralization in part may be genogroup specific, and thus a monovalent vaccine based on the Wa genogroup is likely to protect against the G12 rotaviruses.