Managing HMPV with Covid-19 lessons

Human Metapneumovirus (HMPV) is caused by a type of paramyxovirus that primarily targets the respiratory system, leading to upper and lower respiratory tract infections (URTI and LRTI) in both children and adults. It is distributed globally and follows a seasonal pattern similar to that of influenza viruses.

Initially recognised as a primary cause of respiratory tract infections in children under one year of age, HMPV has since emerged as a significant contributor to respiratory illnesses in adults. In particular, it poses a higher risk for individuals over 65 years of age and those with underlying conditions such as chronic obstructive pulmonary disease (COPD), asthma, cancer, or immunocompromised states, including HIV infection or post-transplant status.

HMPV primarily spread through direct or close contact with contaminated respiratory secretions, such as saliva, droplets, or large-particle aerosols expelled when an infected person coughs or sneezes. Indirect transmission can also occur through contact with contaminated surfaces, such as doorknobs or handles, followed by touching the eyes, nose, or mouth. Infected individuals typically experience flu-like symptoms, including fever, runny nose, body aches, sore throat, and headache. In severe cases, the infection can progress to pneumonia or bronchitis, causing difficulty in breathing, chest pain, wheezing, fatigue, and persistent fever. The incubation period for HMPV generally ranges from three to six days, depending on the severity of the infection.

Diagnosis of HMPV is made using various laboratory techniques, including viral culture, reverse transcriptase-polymerase chain reaction (RT-PCR), antigen detection in respiratory secretions (via immunofluorescence or enzyme immunoassay), and nucleic acid amplification tests (NAAT) to identify the viral genome. Among these, PCR testing is considered the most reliable, providing accurate results within a few hours.

The Covid-19 pandemic significantly influenced public health practices, reinforcing preventive measures that have also helped curb the spread of other respiratory infections, including HMPV. Increased awareness of hygiene and infection control has contributed to the relatively limited spread of HMPV. Simple yet effective practices, such as frequent handwashing, mask-wearing, and proper respiratory hygiene -- covering coughs and sneezes-- remain effective in reducing airborne virus transmission.

Public vigilance regarding symptoms like fever, cough, and breathing difficulties has led to early medical care and self-
isolation, further limiting the viral spread. Many people
continue to wear masks in crowded places such as markets, buses, and hospitals, adding another layer of protection. By maintaining physical distance and exercising caution, individuals can reduce their risk of contracting and spreading HMPV.

Post-pandemic, healthcare systems have strengthened their capacity to handle outbreaks, adopting advanced diagnostic technologies for the rapid detection of pathogens like HMPV. The availability of rapid testing methods like PCR (Polymerase Chain Reaction) and improved outbreak monitoring has made it easier to identify and contain HMPV cases.

In India, hospitals now use the Integrated Health Information Portal (IHIP) to report cases of Severe Acute Respiratory Infections (SARI) and Influenza-like Illnesses (ILI), ensuring accurate surveillance and better tracking of respiratory infections. The lessons learned from Covid-19 --emphasising early detection, effective public health communication, and timely interventions--should be universally applied to combat seasonal respiratory threats.

Currently, treatment for HMPV remains primarily supportive, as no specific antiviral therapy is widely available. However, ribavirin has shown both antiviral and immunomodulatory effects. Palivizumab, a humanised monoclonal antibody, has shown preventive efficacy in high-risk infants. Similarly, motavizumab, a monoclonal antibody developed as an improvement upon palivizumab, provides a potential model for future antibody-based therapies targeting HMPV. Currently, no licensed vaccine for HMPV exists. 

While HMPV may not pose the same global threat as Covid-19, its potential resurgence underscores the importance of vigilance,
preparedness, and resilience as key elements in safeguarding public health.

(Akhter Rasool is a research scholar, ICAR-NDRI, Bengaluru and Jyoti Rawat is a research scholar at School of Bioscience, Himalayan University)