<i>Rotavirus alphagastroenteritidis</i> Circulating Strains after the Introduction of the Rotavirus Vaccine (Rotarix®) in Luanda Province of Angola

Rotavirus alphagastroenteritidis (RVA) remains the leading cause of pediatric diarrhea. Although Angola introduced Rotarix, the human monovalent RVA vaccine since 2014 into its routine childhood immunization program, no follow-up study was developed. The aim of this study was to evaluate the distribution of RVA genotypes among children under five years of age, hospitalized with acute gastroenteritis (AGE), after the introduction of rotavirus vaccine. To achieve this goal, stool samples collected between 2021 and 2022 from children under 5 years of age diagnosed with AGE at six hospitals from Luanda Province were analyzed. The RVA-antigen immunochromatographic test (SD Bioline™, Abbott, USA) was performed and positive samples were genotyped. Thirteen strains were aleatory chosen for further Sanger sequencing. The results showed that the G9[P6] was the most prevalent genotype (17.3%), followed by G9P[8] (16.5%), G2P[4] (14.9%), G3P[6] (13.2%), G8P[6] (11.5%), and less frequently G12P[8] (9.1%), G1P[6] (4.1%), and G1P[8] (2.5%). The genotype combinations G3P[6], G8P[6], and G12P[8] were detected for the first time in Luanda Province. In conclusion, the emergence of new genotype combinations supports the need for continuous surveillance to identify the trend of RVA infection and the emergence of new strains circulating in Luanda Province in the post-vaccination period.