Emerging lineages A2.2.1 and A2.2.2 of human metapneumovirus (hMPV) in pediatric respiratory infections: Insights from India.

OBJECTIVES

Human metapneumovirus (hMPV) is recognized as a significant cause of acute respiratory infections among infants under 5 years of age.

METHODS

Nasal swabs collected from January 2021 to June 2024 were screened to detect hMPV using reverse transcription-quantitative polymerase chain reaction. Furthermore, representative positive samples were sequenced and subjected to phylogenetic analysis.

RESULTS

Of 4519 samples tested, 113 were positive for hMPV. Notably, an outbreak occurred between November 2022 and March 2023, where 56 of 583 (9.6%) patients tested positive. Analysis of the outbreak samples revealed that majority (6.3%) of cases occurred in December and January. hMPV infection was more prevalent in less than 1 year, with 29 (67%) patients with a history of wheezing and 3 (6.9%) with seizures. On the genetic analysis of F protein, 37 samples identified two genotypes as A and B, with subclusters of 29 (85.29%) samples to A2.1, 1 (2.94%) to A2.2.1, and 4 (11.76%) to A2.2.2 within genotype A and one sample clustered with B1 and 2 samples to B2 within genotype B.

CONCLUSIONS

The study underscores the significant prevalence and genetic diversity of hMPV in children in Puducherry, India. Notably, the identification of novel A2.2.1 and A2.2.2 lineages highlights the evolving nature of hMPV.