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Background <p>The effectiveness of Group A Rotavirus (RVA) vaccine in low-income countries remains limited, partly due to the circulation of strains not covered by existing vaccines. Despite the introduction of Rotarix (2014) in Cameroon, no nationwide studies have comprehensively characterized circulating RVA strains. This study provides post-vaccination genotyping data of RVA strains from Douala, Edéa, Nkongsamba (Littoral Region) and Kumba (Southwest region) in Cameroon.</p> Methods <p>A cross-sectional study was conducted on 197 diarrhoeal samples collected from children under five years of age along with their vaccination data from the Littoral region (<i>n</i> = 130; May 2015 - April 2016) and Kumba in the Southwest Region (<i>n</i> = 67; July 2017 - June 2018). RVA NSP3 gene was detected using qRT-PCR and NSP3-positive samples were further analyzed using one-step multiplex RT-PCR for genotyping of wild-type and vaccine strains, with VP4 and VP7 typing performed using nested PCR.</p> Results <p>Of the 197 children enrolled in this study, 63% were fully vaccinated with Rotarix, 22% were unvaccinated, and 15% had unknown vaccination status. Overall, 87 samples were genotyped including 28 (21.5%) from Littoral region and 59 (88.1%) from Kumba, indicating a marked difference in genotyping success across sites. Five VP7 (G) genotypes (G1, G2, G3, G9, G12) were identified with distinct regional patterns. In the Littoral region, G2 (46.4%) and G3 (35.7%) predominated whereas Kumba was dominated by G1 (61.0%) and G12 (37.3%). VP4 (P) genotypes included P [8], P [6], and P [4], with P [8] being the most prevalent in both regions. The Littoral region showed higher genotype diversity with multiple co-circulating strains, particularly G3P [8] and G2P [4] while Kumba showed a more restricted genotypic profile, dominated by G1P [8] (57.6%) and G12P [6] (32.8%). The presence of mixed infections (3.6%) and non-typeable strains (7.1%) further highlight the co-circulation of multiple strains and the potential for reassortment events.</p> Conclusion <p>This study contributes to the limited available post-vaccination description of circulating rotavirus A (RVA) genotypes in the Littoral region and Kumba, Cameroon. Distinct patterns of genotype distribution were observed between the two study areas. In Kumba, G1P [8] and G12P [6] were the predominant genotypes, whereas a wider range of RVA genotypes was detected in the Littoral region. G1P [8] was identified among vaccinated children in both study areas, indicating its continued circulation following vaccine introduction. No statistically significant associations were found between RVA genotype distribution and sex, age, or vaccination status. Overall, the detection of both predominant and less frequently identified RVA genotypes in the post-vaccination period highlights the need for continued molecular surveillance to monitor changes in genotype distribution and evaluate the long-term impact of rotavirus vaccination in Cameroon.</p>

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Post-vaccine surveillance of Group A Rotavirus strains circulating in the Littoral and South West Regions of Cameroon

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  • 发表日期：

    2026年8月5日

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  • Carine Ngah Enjeh,
  • Rahinatou N. Ghapoutsa,
  • Maurice Boda,
  • Mathew D. Esona,
  • Julius M. Nwobegahay,
  • Valantine N. Ndze,
  • Lesley N. Ngum,
  • Palmer M. Netongo,
  • Maximilienne Ascension Nyegue

摘要

Background

The effectiveness of Group A Rotavirus (RVA) vaccine in low-income countries remains limited, partly due to the circulation of strains not covered by existing vaccines. Despite the introduction of Rotarix (2014) in Cameroon, no nationwide studies have comprehensively characterized circulating RVA strains. This study provides post-vaccination genotyping data of RVA strains from Douala, Edéa, Nkongsamba (Littoral Region) and Kumba (Southwest region) in Cameroon.

Methods

A cross-sectional study was conducted on 197 diarrhoeal samples collected from children under five years of age along with their vaccination data from the Littoral region (n = 130; May 2015 - April 2016) and Kumba in the Southwest Region (n = 67; July 2017 - June 2018). RVA NSP3 gene was detected using qRT-PCR and NSP3-positive samples were further analyzed using one-step multiplex RT-PCR for genotyping of wild-type and vaccine strains, with VP4 and VP7 typing performed using nested PCR.

Results

Of the 197 children enrolled in this study, 63% were fully vaccinated with Rotarix, 22% were unvaccinated, and 15% had unknown vaccination status. Overall, 87 samples were genotyped including 28 (21.5%) from Littoral region and 59 (88.1%) from Kumba, indicating a marked difference in genotyping success across sites. Five VP7 (G) genotypes (G1, G2, G3, G9, G12) were identified with distinct regional patterns. In the Littoral region, G2 (46.4%) and G3 (35.7%) predominated whereas Kumba was dominated by G1 (61.0%) and G12 (37.3%). VP4 (P) genotypes included P [8], P [6], and P [4], with P [8] being the most prevalent in both regions. The Littoral region showed higher genotype diversity with multiple co-circulating strains, particularly G3P [8] and G2P [4] while Kumba showed a more restricted genotypic profile, dominated by G1P [8] (57.6%) and G12P [6] (32.8%). The presence of mixed infections (3.6%) and non-typeable strains (7.1%) further highlight the co-circulation of multiple strains and the potential for reassortment events.

Conclusion

This study contributes to the limited available post-vaccination description of circulating rotavirus A (RVA) genotypes in the Littoral region and Kumba, Cameroon. Distinct patterns of genotype distribution were observed between the two study areas. In Kumba, G1P [8] and G12P [6] were the predominant genotypes, whereas a wider range of RVA genotypes was detected in the Littoral region. G1P [8] was identified among vaccinated children in both study areas, indicating its continued circulation following vaccine introduction. No statistically significant associations were found between RVA genotype distribution and sex, age, or vaccination status. Overall, the detection of both predominant and less frequently identified RVA genotypes in the post-vaccination period highlights the need for continued molecular surveillance to monitor changes in genotype distribution and evaluate the long-term impact of rotavirus vaccination in Cameroon.