Prevalence of Different Dengue Serotypes in Northern India, 2021-2022: A Tertiary Care Hospital-Based Study.

Dengue fever is a substantial emerging and reemerging arboviral virus in tropical and subtropical areas that seriously threatens public health worldwide. India is experiencing rising dengue epidemics in urban and rural regions linked to all four serotypes. The objective is to examine the serotypes and genotypes of the circulating dengue virus (DENV) at a tertiary care center in eastern Uttar Pradesh, India, from 2020 to 2021. This retrospective cross-sectional observational study involved dengue patients from January 2021 to December 2022. The genetic analysis of the circulating DENV was conducted by amplifying the partial CprM (511-bp) gene using nested reverse transcriptase polymerase chain reaction (RT-PCR), followed by sequencing. Only those positive for NS1 antigen (n = 581) were included in the study. A total of 204 cases (35.1%) were seropositive, with 96 cases (37.4%) out of 257 in 2021 and 108 cases (33.3%) out of 324 in 2022. With 119 cases (58.3%), men were most affected. The nested RT-PCR for dengue revealed three DENV-1 to DENV-3, except for DENV-4. DENV-2 and DENV-3 were the most predominant serotypes, with 98 (48%) and 94 (46%) cases, respectively. Conversely, DENV-1 was the least prevalent with cases 3 (1.6%). Unfortunately, 35 (17.2%) of the 204 cases died. DENV-2 had the highest mortality rate, with 23 deaths (65.7%). In cases with DENV-3, nine (25.7%) died. This study revealed regional disparities in DENV serotype prevalence in India. If regional differences in the most common serotypes and genotypes are identified early in the season, molecular surveillance may predict major dengue outbreaks and severity.