A familiar virus caught in the spotlight

Cases of a common respiratory virus called human metapneumovirus or HMPV are surging in several Asian countries, but experts opine that the situation shouldn’t trigger fears of a larger global health threat.

In mid-December last year health agencies in China reported an overall increase in respiratory infections, including an HMPV uptick in children under 14 years old in northern China. Reports of a hospital allegedly flooded with cases further fuelled alarm and attention to this lesser known yet common winter respiratory disease.

HMPV falls into the same mix of winter bugs as influenza and respiratory syncytial virus (RSV), which often peak during this time of year in the Northern Hemisphere. Common HMPV symptoms, such as a runny nose, coughing and fever, are typically mild. Young children, older adults and people who are immunocompromised may be at a higher risk of severe disease, however.

China’s relatively large case count has prompted the nation and nearby countries to increase surveillance. Cases have also been detected in Malaysia, India and Kazakhstan. Experts note that HMPV has been occurring in humans around the world for decades, however.

“The virus has circulated for at least 60 years, and genetic evolutionary studies suggest that it diverged from a bird virus between 200 to 400 years ago,” John Williams, a paediatrician and infectious diseases professor at the University of Wisconsin–Madison, who has studied HMPV for more than 20 years, has been quoted as saying.

Fears of a Covid-19 style pandemic are overblown, experts have said, noting that pandemics are typically caused by novel pathogens, which is not the case for HMPV.

The virus is globally present and has been around for decades. This means people across the world have “some degree of existing immunity due to previous exposure”, experts have added.

Like many respiratory infections, HMPV is most active during late winter and spring — some experts say this is because the viruses survive better in the cold and they pass more easily from one person to another as people stay indoors more often.

In northern China, the current HMPV spike coincides with low temperatures that are expected to last until March.

In fact many countries in the northern hemisphere, including but not limited to China, are experiencing an increased prevalence of HMPV, Jacqueline Stephens has been quoted in a report. She is an epidemiologist at Flinders University in Australia.

“While this is concerning, the increased prevalence is likely the normal seasonal increase seen in winter,” she added.

Data from health authorities in the US and UK shows that these countries, too, have been experiencing a spike in HMPV cases since October last year.

HMPV is a virus that will lead to a mild upper respiratory tract infection — practically indistinguishable from flu — for most people.

First identified in the Netherlands in 2001, the virus spreads through direct contact between people or when someone touches surfaces contaminated with it.

Symptoms for most people include cough, fever and nasal congestion.

It belongs to the Pneumoviridae, Metapneumovirus genus. HMPV is an enveloped single-stranded negative-sense RNA virus.

The very young, including children under two, are most vulnerable to the virus, along with those with weakened immune systems, including the elderly and those with advanced cancer.

If infected, a small but significant proportion among the immunocompromised will develop more severe disease where the lungs are affected, with wheezing, breathlessness and symptoms of croup.

Complications associated with HMPV include pneumonia, bronchiolitis, worsened respiratory conditions like asthma or chronic obstructive pulmonary disease (COPD) and bacterial pneumonia.

HMPV infection can cause outbreaks. However, experts in India said there’s no need to worry.

Dr Atul Goel, Director-General of Health Services, reassured the public that there is no cause for alarm regarding the current situation.

He told news agency ANI: “We have analysed the data of the respiratory outbreaks within the country, there is no such substantial increase in 2024 data.” He also mentioned that respiratory infections are common during winter months, and “our hospitals are fully prepared for that with the necessary supplies and beds.”

So far in India, till this report was filed, eight cases of HMPV, including two in Karnataka, Gujarat (1), and Tamil Nadu (2) have been reported. All the cases were detected in young children ranging from three months old to 13 years old. Two new cases were reported from Nagpur on Tuesday. On Wednesday, another HMPV case was confirmed in Mumbai, taking the total tally of confirmed HMPV cases in Maharashtra to three.

Children and elderly with cold and cough must stay at home to prevent the spread of HMPV, a respiratory illness currently seeing an uptick in the country, former AIIMS Director Dr Randeep Guleria was quoted as saying in a media report. He added that prevention is most important.

Guleria urged for following public health measures like regular handwashing and the use of masks, which can protect from other respiratory illnesses like flu.

“I think the lessons we learned from Covid are something that everyone should follow, especially during this time, because this will protect you not only from the HMPV but even from Covid or other influenza-related viruses”.

It is important to follow “Covid appropriate behaviour such as wearing a mask, regular hand washing, cough etiquettes like covering your cough. If you don’t have a tissue or a handkerchief to cover your cough/sneeze in your arm or elbow so that you don’t spread the infection, avoid going to crowded places,” the noted pulmonologist said.

Guleria said the virus is not new and only causes mild infection in young children and elderly persons. He added the infection is self-limiting and must not be treated with antibiotics but with proper hydration and nutrition.

Meanwhile, Union minister JP Nadda, in a video message, said: “It (the virus) was first identified in 2001 and has been circulating in the entire world since many years. It spreads through the air by the way of respiration. This can affect persons of all age groups. The virus spreads more during the winter and the early spring months.”

The Health Ministry, the Indian Council for Medical Research (ICMR), and the National Centre for Disease Control are keeping a close watch on the situation in China, as well as in neighbouring countries, Nadda assured.

“There is no reason to worry. We are closely monitoring the situation,” he added.

In response to the first reported case of HMPV infection in Bengaluru, the Maharashtra, Telangana, and Delhi state governments have issued advisories to prevent the spread of the virus.

Only three percent of the people who are tested for Influenza-Like Illnesses (ILI) or Severe Acute Respiratory Illnesses (SARI) are found infected with HMPV, which has triggered concerns five years after COVID-19 first emerged, World Health Organisation (WHO) former chief scientist Soumya Swaminathan has said.

In an interview with a media channel, Swaminathan also added that the HMPV infection has been in circulation in India for several years, but has come as a “bit of shock” to the people as it is not frequently talked about.

The health scientist also added that there is no correlation between HMPV and COVID-19, which has killed millions worldwide ever since it first broke out in China in 2020. “Coronavirus is another group of viruses. The HMPV is a very different kind of virus.”

She said there doesn’t seem to be any new mutation and the HMPV virus is the same, whether it is in China or India. “But obviously, the National Institute of Virology and others are going to keep tracking the virus to ensure that there is nothing to be concerned about,” she said.

The Centre has advised states to step up surveillance for respiratory illnesses, including ILI and SARI, and spread awareness about the prevention of transmission of HMPV.

Union Health Secretary Punya Salila Srivastava recently chaired a virtual meeting with states and Union Territories to take stock of respiratory illnesses and HMPV cases in the country and public health measures for their management, a health ministry statement said.

Views expressed are personal