What is the Human Metapneumovirus (HMPV)?

By: Geraldus Sigap

Human metapneumovirus (HMPV) is a respiratory virus that has been affecting people worldwide for decades, yet it remains relatively unknown to many. Discovered in 2001, this virus has likely been circulating for over 60 years, causing mild to severe respiratory illnesses in people of all ages. Understanding HMPV is crucial, as it can lead to serious health issues, particularly in vulnerable groups such as young children, older adults, and individuals with weakened immune systems.

What is HMPV?

HMPV belongs to the Pneumoviridae family, a group of enveloped RNA viruses that includes other respiratory pathogens like respiratory syncytial virus (RSV). It is most closely related to avian metapneumovirus, although it does not infect birds. HMPV primarily targets the respiratory tract, where it can cause both upper and lower respiratory infections, ranging from mild colds to severe conditions like pneumonia and bronchiolitis.

HMPV is categorized into two major subgroups, A and B, with each subgroup further divided into clades. These subtypes circulate concurrently, but one may dominate during a specific season or outbreak. Despite minor genetic differences among subtypes, their clinical impact is generally similar, and there is no evidence that one type is more severe than another.

In late 2024, a significant surge in HMPV cases was reported in China, with the virus accounting for 6.2% of positive respiratory illness tests and 5.4% of related hospitalizations, surpassing other viruses like COVID-19, rhinovirus, and adenovirus. In Indonesia, the Ministry of Health has acknowledged the presence of HMPV. Health Minister Budi Gunadi Sadikin emphasized that HMPV is not a new virus and resembles the common flu. He urged the public not to panic, noting that the human immune system is familiar with this virus and can respond effectively. The Minister also highlighted that while HMPV cases have been detected, they primarily involve children, and the virus does not pose the same threat level as COVID-19.

How is HMPV Transmitted?

HMPV spreads through close contact with infected respiratory secretions. This can occur via droplets from coughs or sneezes, direct contact such as shaking hands, or touching contaminated surfaces and then touching your face. The virus does not spread through tiny airborne particles like some other respiratory viruses, so maintaining a physical distance of at least six feet can significantly reduce the risk of transmission.

Nosocomial, or hospital-acquired, infections have also been reported, especially in pediatric wards and long-term care facilities. These outbreaks can have high attack rates, affecting a large percentage of residents and staff, emphasizing the importance of strict infection control measures.

Symptoms of HMPV Infection

The symptoms of HMPV infection vary widely, from mild cold-like symptoms to severe respiratory distress. Common symptoms include:

Cough
Nasal congestion and runny nose
Fever
Wheezing
Shortness of breath
Sore throat
Fatigue

In severe cases, particularly in infants, older adults, or immunocompromised individuals, the virus can cause bronchiolitis, pneumonia, or acute respiratory distress syndrome. These conditions may require hospitalization and even intensive care.

Who is at Risk?

While HMPV can infect individuals of all ages, certain groups are more vulnerable to severe disease. These include:

Young children: Infants and children under the age of five are at a higher risk of developing serious respiratory symptoms. Studies show that most children have been infected with HMPV by the age of five.
Older adults: People aged 65 and above are more likely to experience severe respiratory complications.
Immunocompromised individuals: Patients undergoing chemotherapy, organ transplant recipients, and those with chronic illnesses like diabetes or HIV are particularly susceptible.
People with underlying respiratory conditions: Conditions such as asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis can exacerbate the severity of HMPV infections.

Diagnosis of HMPV

Diagnosing HMPV can be challenging, as its symptoms overlap with those of other respiratory illnesses like influenza, RSV, or even COVID-19. However, advanced diagnostic tools such as reverse-transcriptase polymerase chain reaction (RT-PCR) can accurately detect the virus in respiratory samples. RT-PCR is the gold standard for HMPV diagnosis due to its high sensitivity and specificity.

How is HMPV Treated?

There is currently no specific antiviral treatment for HMPV. Management focuses on supportive care, which includes:

Rest and hydration to help the body recover
Over-the-counter medications to reduce fever and relieve symptoms like congestion or sore throat
Supplemental oxygen or mechanical ventilation in severe cases requiring hospitalization
Antibiotics are not effective against viral infections like HMPV unless there is a secondary bacterial infection. For individuals with underlying health conditions or compromised immune systems, close monitoring is essential to prevent complications.

Prevention of HMPV

Preventing HMPV infections involves simple but effective hygiene practices. These include:

Frequent handwashing with soap and water for at least 20 seconds
Avoiding close contact with people who are sick
Regularly disinfecting frequently touched surfaces, such as doorknobs and mobile phones
Covering your mouth and nose with a tissue or elbow when coughing or sneezing
In healthcare settings, contact precautions such as wearing gloves and masks can help prevent the spread of HMPV, especially in vulnerable populations.
Seasonal Patterns and Global Spread

HMPV exhibits distinct seasonal patterns, similar to other respiratory viruses. In temperate regions like the United States, the Netherlands, and the United Kingdom, the virus tends to peak in late winter and early spring. However, in tropical regions such as Hong Kong, outbreaks are more common in late spring and summer.

Since its discovery, HMPV has been identified in countries across the globe, highlighting its widespread presence and the importance of ongoing surveillance and research to better understand its behavior and impact.

If you or your loved ones are experiencing persistent respiratory symptoms such as a cough, wheezing, or shortness of breath, seeking expert medical care is crucial. At RS Abdi Waluyo, our pulmonology specialists provide comprehensive diagnostic and treatment services for respiratory conditions, including HMPV-related infections.

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