HMPV a major cause of respiratory distress among kids, new strains A2.2.1 and A2.2.2 shows virus is evolving: Study

While HMPV infection cases have created panic in India, especially at a time when outbreaks have been reported in China, health experts are urging people not to panic.

A new study has shed light on human metapneumovirus and its impact on pediatric health.

The study by researchers from Regional Level Viral Research & Diagnostic Laboratory (RVRDL), Department of Microbiology, Jawaharlal Institute of Post-Graduate Medical Education and Research (JIPMER), Puducherry, India and Department of Pediatrics, JIPMER, Pondicherry, India has found new lineages of A2.2.1 and A2.2.2 of the HMPV.

"A notable outbreak of human metapneumovirus (hMPV) was detected between November 2022 and March 2023, with a 9.6% positivity rate among tested patients," the researchers have said. Human metapneumovirus (hMPV) is recognized as a significant cause of acute respiratory infections among infants under 5 years of age.



For the study, the researchers examined nasal swabs collected from January 2021 to June 2024. Using reverse transcription-quantitative polymerase chain reaction they screened for the HMPV. The researchers found that majority of the cases happened between December and January.

"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," the researchers have said.

HMPV is a respiratory virus classified into two main genetic groups: A and B, each with subgroups A1, A2, B1, and B2. These strains exhibit genetic diversity but share similarities in causing respiratory infections, ranging from mild cold-like symptoms to severe lower respiratory issues.

Group A strains (A1, A2a, A2b) are more often associated with outbreaks, particularly in young children and the elderly. Group B strains (B1, B2) are also prevalent but may differ slightly in virulence and geographic distribution. Both groups mutate over time, which complicates vaccine and antiviral development, making ongoing surveillance essential.

Major findings of the study

hMPV infection was most prevalent in children under 1 year old, with 67% experiencing wheezing and 6.9% experiencing seizures.

A notable outbreak of human metapneumovirus (hMPV) was detected between November 2022 and March 2023, with a 9.6% positivity rate among tested patients.

Peak infections occurred in December and January, aligning with studies suggesting a winter-spring prevalence

The findings of the study have been published in IJID Regions journal.