‘HMPV Is Common, Most Will Recover On Their Own’

On January 6, the government issued a press release which said that “based on current data from ICMR and the Integrated Disease Surveillance Programme (IDSP) network, there has been no unusual surge in Influenza-Like Illness (ILI) or Severe Acute Respiratory Illness (SARI) cases in the country”. It mentioned that two cases that had been reported in Karnataka were “..identified through routine surveillance.”

In another press release on January 7, the government said that HMPV, which was discovered in 2001, is one of the many respiratory viruses that can cause infections in people of all ages particularly during the winter and early spring months and that there was “no cause of concern for the public from HMPV”.

“I think much of the reporting is sheer hype, and happens only because the combination of words “China” and “virus” attracts inordinate attention,” said Gautam Menon, Dean (Research) & Professor, Departments of Physics and Biology, Ashoka University in an interview.

Menon was appointed a commissioner on the Lancet Commission on Strengthening the use of Epidemiological Modelling of Pandemic Diseases and a member of the World Health Organization’s Technical Advisory Group on Embedding Ethics in Health and Climate Change Policy.

He felt that it was unlikely that there would ever be a situation like the second wave of Covid-19 as far as HMPV is concerned. But Menon said we should be prepared for the possibility of bird flu (H5N1) spilling over to humans and changing to facilitate human-to-human transmission.

Edited excerpts:

A few cases of HMPV have been confirmed in Bengaluru and Gujarat in infants and young children. Reports about surging cases in China have created worries. What is the nature of the virus and how long has the virus been around?

The virus is likely several decades old, although it first came to light almost two-and-a-half decades ago [in 2001] after samples taken from presumed influenza cases reported from the Netherlands were investigated using modern methods of detecting viruses.

What is the usual protocol for testing and surveillance for HMPV? Does a flu vaccine provide protection?

There are two methods: One involves sequencing the virus genome, while the other looks for characteristic antigens or antibodies in body fluids.

It is unclear whether the flu vaccine might provide protection, since this virus is not in the same class as the influenza virus. It is more related to another respiratory virus called RSV, also responsible for flu-like symptoms but unrelated to influenza.

Why is there an increase in reporting now? What is the likelihood that transmission was due to foreign travel?

There is always an increase in respiratory illness in the cold season, as people are in closer proximity in homes. The virus may also thrive better in colder climates.

I think much of the reporting is sheer hype, and happens only because the combination of words “China” and “virus” attracts inordinate attention. As I said, the virus is common and is known to circulate, so I think it unlikely that travel had anything to do with the Indian cases.

A study on the global burden of acute lower respiratory infection associated with HPMV in children under five years in 2018 showed that infants have disproportionately high risks of severe HMPV infections--more so in low- and lower-middle-income countries. How do you think India is placed in terms of handling HMPV among infants?

It is currently unclear what fraction of respiratory illness in children in India is attributable to HMPV. From what is known elsewhere, only about 5-10% may be directly attributable. We should deal with it as we deal with any respiratory infection in children--most will recover on their own and only a small fraction will develop more severe symptoms that may call for hospitalisation.

We must protect the elderly and the very young, that’s the bottom line, but standard methods of doing this--washing hands, ensuring they are not in proximity to those with coughs and colds, and wearing masks around elderly and infection-prone people--should be sufficient.

How is HMPV different from the SARS-CoV-2 virus–in terms of severity and how quickly it spreads? How is the cycle from catching the infection to developing immunity?

Unlike SARS-CoV-2, this is not a novel virus. It has been in circulation for several decades now and it is likely that some or most of us have been exposed to it before. This means that overall its impact will be milder, although we know less, at this point, about how fast the HMPV virus mutates.

How does this affect the elderly and those with comorbidities? Considering the virus is known and has been around for decades, why isn’t the immune response as strong among these groups?

In general, elderly people are more susceptible to respiratory infections, mainly because their immune response is less robust with age. This has less to do with the virus itself but more with the body’s response to it.

We had reported that several oxygen plants in India’s hospitals are in disrepair or not in use with demand for medical oxygen subsiding since the Covid pandemic. Do you envisage pressure on hospital beds? If so, how prepared do you think we are to provide necessary care?

I personally believe that it is unlikely that we will ever be in a situation like the second wave of COVID-19 as far as HMPV is concerned. However this is not the only public health threat on the horizon. The possibility of bird flu (H5N1) spilling over to humans and changing to facilitate human-to-human transmission would be the most worrying prospect. To prepare for that is important, and restoring dormant oxygen plants to functionality would be a large part of that preparation.

What would in-patient care for severe cases look like?

There are no specific treatments or antivirals, so supportive treatment is what is called for. Oxygen for those who require it, ICU support in critical cases--this would largely be similar to COVID-19.

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