TITLE:
Distribution of Rotavirus Strains before and after Introduction of the Rotarix Vaccine in the Expanded Program on Immunization (EPI) in Senegal
AUTHORS:
Diop Amadou, Diéye Baïdy, Sonko Mouhamadou Abdoulaye, Touré Mamadou, Thiongane Aliou, Faye Papa Moctar, Diallo Aliou, Diop Boly, Niang Aïssatou Ahmet, Diallo Fatoumata, Sarr Habibou, Dia Mouhamadou Lamine
KEYWORDS:
Genotypes, Rotavirus, Monovalent Vaccine, Senegal
JOURNAL NAME:
Open Journal of Medical Microbiology,
Vol.15 No.4,
December
1,
2025
ABSTRACT: Senegal introduced the monovalent Rotavirus vaccine into its Expanded Program on Immunization in November 2014. The main objective of this study was to monitor the distribution of Rotavirus strains following vaccine introduction in Senegal. Materials and Methods Stool specimens were collected from children under 5 years of age who were hospitalized or under observation at the Albert Royer National Children’s Hospital in Dakar from January 1, 2011 to December 31, 2020. Rotavirus antigen detection was performed using an enzyme-linked immunosorbent assay (ELISA), and molecular characterization of ELISA-positive samples was conducted at the West African Regional Rotavirus Reference Laboratory in Accra, Ghana. Results: A total of 313 ELISA-positive samples underwent molecular characterization: 235 samples (75.07%) were collected before vaccine introduction and 78 samples (24.93%) after. During the pre-vaccine period, VP7 genotypes G1 and G12 and VP4 genotypes P[6] and P[8] accounted for more than 90% of circulating G and P genotypes. In the post-vaccine period, VP7 genotypes G3 and G1 represented over 47% of strains, while VP4 genotypes P[6] and P[8] comprised nearly 90%. The predominant strain combinations were G12P[8] and G1P[6] before vaccine introduction, shifting to G3P[8] and G1P[8] afterward. Conclusion G12P[8] and G1P[6] genotypes predominated in the pre-vaccine era, whereas G3P[8] and G1P[8] were the most frequent after vaccine introduction. Continuous surveillance in the post-vaccine period is essential to monitor circulating Rotavirus strains and detect unusual or emerging genotypes.