Rotavirus genotype dynamics in Pakistan: G9 and G12 emerging as dominant strains in vaccinated children (2019).

Rotavirus A (RVA) is a leading cause of severe gastroenteritis in children worldwide, and vaccination has become a pivotal strategy to reduce the associated morbidity and mortality. This study presents a molecular characterization of RVA genotypes circulating among vaccinated children in Pakistan during the year 2019. A total of 510 stool samples were collected from children of up to five years of age presenting with acute gastroenteritis symptoms in Rawalpindi, Islamabad regions of Pakistan. The RVA antigen was detected using ELISA on these samples. RVA G/P genotyping was performed on ELISA positive samples using Multiplex semi-nested reverse transcriptase PCR. RVA was found in 130 fecal samples, with an overall prevalence of 25.4 %. G9P[8] (20 %) is the most prevalent genotype, followed by G12P[6] (17 %), G3P[8] (14 %), G1P[8] (12 %), G2P[4] (10 %), G12P[8] (7 %), G9P[6] (7 %), G3P[6] (6 %), G3P[4] (4 %) and G1P[6] (3 %) respectively. There is a statistically significant difference (p < 0.05) found in the group age (in months) of RVA gastroenteritis cases as detected by RT-PCR. The highest number of positive cases was found in the age range from 0 to 6 months, followed by 7-12 months, 13-24 months, and 25-60 months, respectively. Dehydration is statistically significantly associated (p˂ 0.05) in RVA gastroenteritis cases compared to those who tested negative. This study emphasizes the significance of maintaining a continuous surveillance system and conducting genomic analysis of RVA genotypes in children upto the age of 5 years. This is essential for tracking the circulation of RVA genotypes. The results from this research enhance our comprehension of how RVA genotypes are changing over time in Pakistan, underscoring the ongoing necessity for improving vaccine coverage and effectiveness. This, in turn, can help reduce the impact of RVA-related illnesses in children.