BHUBANESWAR: Five years after the global outbreak of Covid-19, the human metapneumovirus (HMPV) is grabbing headlines as China has reportedly been witnessing a surge in cases, especially among children and elderly people. The central government has been alert and closely monitoring the respiratory and seasonal flu cases across the country.
Initially identified in 2001, HMPV is a major cause of acute respiratory infections worldwide, especially in children, older adults, and individuals with weakened immune systems. It is found to be more common during winter and early spring.
Dr Srivatsa Lokeshwaran, head of interventional pulmonology and lung transplant department at Aster Whitefield Hospital, Bengaluru, said the number of cases being reported in China, especially in the northern parts, has been on the rise.
“Although HMPV is an old virus, a new mutation could have led to the recent spike in infections. As HMPV does not have definitive treatment, only supportive care like most viruses is recommended. Since there is no vaccine for it, prevention is the best way forward. After the China outbreak is reported to WHO, surveillance has been intensified across the world,” he said.
With symptoms similar to the common cold, the virus often causes upper respiratory infections and can sometimes cause lower respiratory infections like pneumonia, asthma flare-ups, and make chronic obstructive pulmonary disease (COPD) worse. Its incubation period can vary between three to six days.
What is HMPV?
Human metapneumovirus is a non-segmented single-stranded RNA virus from the paramyxoviridae family. HMPV is unlike the corona virus as it usually affects children, aged less than 12 years, and elderly people. Believed to have originated from birds, the virus spreads through respiratory droplets, direct contact, or contaminated surfaces, making it highly transmissible in community settings.
The usual symptoms are running nose, sneezing, cough, breathlessness, wheezing and high grade fever, sometimes leading to bronchiolitis as well as pneumonia. The virus binds to the mucosa of the nose and gains entry to lungs. It can be diagnosed through clinical evaluation and laboratory tests.
The virus can affect both upper and lower respiratory tract. It can affect all age group but can cause severe infection in young children, elderly, people with chronic obstructive lung disease (COPD) or asthma and in immunocompromised individuals like people on chemotherapy or transplant recipients.
Dr Niroj Mishra, a Bhubaneswar-based senior internal medicine specialist, said though the symptoms of HMPV resemble the common cold, it can lead to severe illness in some individuals in first infections, putting young children at higher risk of complications while subsequent infections typically result in milder and cold-like symptoms.
“The virus can cause severe illness in older adults, especially those with pre-existing respiratory conditions, and people with weakened immune systems. After the global health crisis caused by the Covid-19 pandemic, HMPV is a reminder of the need for global vigilance against emerging zoonotic respiratory viruses,” Dr Mishra said.
How is HMPV different from Covid-19?
Both HMPV and Covid-19 are respiratory infections spreading via respiratory droplets. The epidemiology and clinical presentations of both infections are almost the same.
However, Covid-19 has demonstrated high rate of transmission from both symptomatic and asymptomatic patients, having higher fatality rate and causing severe pneumonia, acute respiratory distress syndrome (ARDS) and multi-organ involvement, sometimes leaving long-term effects known as Long Covid.
Dr Subhashree Samantaray, associate consultant, Infectious Diseases, Manipal Hospitals, Bhubaneswar, said HMPV causes mild to moderate illness in most of the cases and is often self-limiting, except in certain high risk groups.
In immunocompromised patients, it can lead to secondary bacterial infections making the disease more severe and difficult to treat. This may result in higher rates of ventilator dependence, hypoxemia and longer hospital stays, she said.
“HMPV is primarily transmitted by symptomatic individuals, and asymptomatic transmission is less common. Most importantly, Covid-19 has multiple approved vaccines and antiviral medications owing to its proven pandemic potential. But HMPV does not have any recommended vaccine or specific antiviral treatment, because of its milder course and self-limiting nature," Dr Samantaray said.
No cause for panic
HMPV infection has been detected in India in the past and is known to have caused acute respiratory infections (ARIs) in the past. Even as eight new cases have been reported so far in the country, health experts said there is no reason to panic.
The infection due to HMPV is not fatal and many individuals recover uneventfully with symptomatic treatment, said Dr Suchismitha Rajamanya, lead consultant and head of Internal Medicine Department at Aster Whitefield Hospital.
“It does not cause fatality in most patients and many times it is self limiting. Few case studies have, however, shown that the fatality rates range between 25-30%,” she said.
The prevention of HMPV is similar to any other respiratory infection – covering your mouth and nose while sneezing/coughing, washing hands, wearing masks in crowded places, and reporting to the health facility, if need arises.
As there is no specific antiviral treatment for HMPV, management focuses on relieving symptoms and supporting respiratory function. As part of symptomatic treatment, doctors prescribe fever reducers like paracetamol for fever and pain, and nasal saline drops or humidifiers to ease nasal congestion along with hydration. In case of severity, patients can be hospitalised for oxygen therapy or ventilator support.
“However, data is awaited regarding the consequences of the virus in the present variant and the complications associated with the people affected. We got to be concerned about any viral outbreak from the lessons learnt during Covid pandemic. But there is no need to panic as it appears to be a local outbreak. The government is monitoring closely and there will be interventions in place to check the spread of the virus,” Dr Lokeshwaran added.