You May be Having the hMPV, Not COVID-19 or Flu. Here’s How to Know

As the seasons change, a new health concern is emerging in Australia: the Human Metapneumovirus (hMPV). The virus is seasonal in nature and typically thrives in the late winter and spring in Australia, around the same time as the flu season. During this time, cases of respiratory illnesses tend to surge, making it prime time for hMPV to spread. With its symptoms bearing a striking resemblance to both COVID-19 and the flu, the natural inclination for individuals experiencing these symptoms is to seek a COVID-19 or influenza tests. 

This is where the conundrum arises. Rapid antigen tests (RATs) have become a popular tool for diagnosing COVID-19 or the flu (if one is using the 3-in-1 combination test), due to their convenience and quick results, however, hMPV does not appear on these tests since they’re not equipped to detect human metapneumovirus antigens.

As a result, individuals who repeatedly test negative on RATs while still experiencing symptoms may start to question what is truly afflicting them. The similarity in symptoms between hMPV, COVID-19, and the flu can lead to confusion and misdiagnosis. This not only impacts individuals' ability to seek appropriate care but also poses a risk in terms of public health.

What is human metapneumovirus (HPMV)?

hMPV, is actually not a recent discovery. In fact, this lesser-known respiratory virus was first identified in the Netherlands in 2001. This virus belongs to the Pneumoviridae family and is closely related to the respiratory syncytial virus (RSV). hMPV is a common respiratory pathogen known to cause a wide range of respiratory tract infections, especially in young children, and those with compromised immune systems. Like influenza A and RSV, hMPV is also a major contributor to the burden of winter-time respiratory illnesses in older adults.

How is human metapneumovirus spread?

Like many respiratory viruses, hMPV is primarily spread through respiratory droplets. When an infected person talks, coughs, or sneezes, they release tiny droplets containing the virus into the air. These droplets can be inhaled by people in close proximity to the infected individual. Touching surfaces contaminated with the virus and then touching the face can also lead to transmission.

Human metapneumovirus symptoms

The symptoms of Human Metapneumovirus (hMPV) infection can vary widely, ranging from mild to severe, and they are similar to those caused by other respiratory viruses such as the common cold, flu, or COVID-19. Common symptoms of hMPV infection include:

1. Cough 
2. Runny or stuffy nose
3. Sore throat
4. Fever
5. Shortness of breath
6. Wheezing

Not everyone infected with hMPV will experience all of these symptoms, and the severity of symptoms can vary from person to person. In some cases, especially in healthy individuals, hMPV infection may cause only mild symptoms or even be asymptomatic (showing no symptoms at all).

Severe cases, however, may involve pneumonia or bronchitis, which can be life-threatening, particularly in infants and individuals with compromised immune systems.

How HPMV is diagnosed

Human Metapneumovirus (hMPV) is diagnosed through a combination of clinical evaluation and laboratory testing. Healthcare providers may suspect hMPV infection based on the patient's symptoms and medical history, especially during seasons when hMPV is known to be circulating.

Laboratory testing:

• Molecular Tests (PCR): The most common method for diagnosing hMPV is through reverse transcription-PCR (RT-PCR). This method is reported to be highly sensitive and specific for identifying hMPV.
• Viral culture - In some cases, viral culture may be used to isolate and confirm the presence of hMPV in respiratory samples, however, viral culture is less commonly used than PCR due to its slower turnaround time.
• Antigen tests - Rapid antigen tests (RATs) are less commonly used for diagnosing hMPV. There are rapid antigen tests assays that are available to detect hMPV such as the direct fluorescent-antibody (DFA) assay but further improvements need to be done for the sensitivities of the assays. A study on the performances on the DFA assays showed that they all have lower sensitivity, especially when hMPV viral loads are low.

Differential diagnosis

Since the symptoms of hMPV can overlap with those of other respiratory infections, such as influenza and respiratory syncytial virus (RSV), healthcare providers may consider these other possibilities and may conduct additional tests to differentiate between these viruses.

Imaging

In some cases, imaging studies like chest X-rays may be used to assess the extent of lung involvement, especially if there is concern about pneumonia or lower respiratory tract complications.

How long are you contagious with human metapneumovirus?

The contagious period for Human Metapneumovirus (hMPV) can vary from person to person and is influenced by several factors, including the individual's age, overall health, and the severity of their illness. In general, the incubation period of hMPV is 3 to 6 days.

• Before symptoms: It is possible for individuals infected with hMPV to spread the virus to others even before they start showing symptoms. This pre-symptomatic period can last for a day or two before the onset of symptoms.

• Peak contagiousness: The highest viral shedding (the release of the virus from the respiratory tract) usually occurs during the early stages of illness, particularly in the first 2 to 5 days after symptoms begin. This is when individuals are most contagious to others.

After symptoms: hMPV shedding can continue for several days to weeks after the onset of symptoms, especially in children and individuals with weakened immune systems. The duration of viral shedding after symptoms vary widely among individuals. If your symptoms last for more than 2 weeks, you’ll need to seek medical help.

hMPV vs COVID-19 vs Flu symptoms

Because these respiratory viruses can feel very similar at first, symptoms alone do not always tell you exactly which virus you have. There is a lot of overlap between hMPV, COVID-19 and influenza, especially when it comes to cough, fever, sore throat, runny nose, fatigue and body aches. Here are some of the key differences:

Is there any symptom that points more strongly to COVID-19?

A new loss of taste or smell is still one of the symptoms more strongly linked with COVID-19 than with hMPV or flu, although not everyone with COVID gets it. COVID symptoms can also range from mild upper respiratory symptoms to fever, body aches, fatigue and shortness of breath.

Read related article: Long COVID: What We Now Know & Why COVID Still Matters

What tends to feel more like the flu?

Flu often has a more sudden onset and is well known for making people feel unwell quickly, with symptoms like fever, chills, headache, body aches and fatigue. A cough and sore throat are also common.

Read related article: Subclade K Influenza: What Australians Need to Know About the Latest Flu Variant

Can you tell the difference without testing?

Not always. Because the symptoms overlap so much, it can be difficult to know which virus is responsible based on symptoms alone. Testing may be useful when it affects treatment decisions, isolation decisions, or the level of medical attention needed.

How long does it take to recover from human metapneumovirus?

Recovery from hMPV infection commonly occurs on its own, and the duration of recovery can vary depending on various factors. Generally, most individuals infected with hMPV will recover within a relatively short timeframe. In most cases, hMPV infections clear up on their own, with individuals typically experiencing significant improvement within 7 to 10 days after the onset of symptoms. During this time, the body's immune system works to combat the virus, leading to a gradual resolution of symptoms.

In severe cases, especially in high-risk groups such as young children, individual with compromised immune system or those with existing respiratory condition, recovery may be longer.

How to manage hMPV and prevent the disease?

Management of Human Metapneumovirus (hMPV) infection primarily focuses on coping with the symptoms, as there is currently no specific vaccine or antiviral treatment available for hMPV.

Here are ways to manage hMPV and promote recovery:

• Get plenty of rest to allow your body to recover.
• Stay well-hydrated by drinking fluids such as water, clear broths, herbal teas, and oral rehydration solutions.
• Use over-the-counter (OTC) medications, that includes ibuprofen, cough suppressants, decongestants, or sore throat lozenges.
• Use a humidifier in your room, especially if the air is dry.
• Avoid smoking and exposure to secondhand smoke.
• Practice good respiratory hygiene by covering your mouth and nose when coughing or sneezing with a tissue or the inside of your elbow. Dispose of tissues properly.
• Practice preventive measures to reduce the risk of transmission to others, such as wearing a mask and maintaining physical distance.

Ways to manage and prevent hMPV

Preventing the spread of Human Metapneumovirus (hMPV) and other respiratory infections requires a combination of personal hygiene practices and effective disinfection measures. This includes:

• Practicing good hand hygiene by regularly washing your hands with soap and water or using hand sanitisers wherever you go.

• Cover your mouth and nose with a tissue or the inside of your elbow when you cough or sneeze. Dispose of tissues properly, and avoid using your hands to cover your mouth and nose.

• In situations where close contact with others is unavoidable, such as crowded indoor settings or healthcare facilities, wearing face masks can help reduce the risk of hMPV transmission.

• Refrain from touching your face, especially your eyes, nose, and mouth, to prevent the transfer of the virus from contaminated surfaces to mucous membranes.

Cleaning and disinfection tips during hMPV, COVID-19 or flu season

Good cleaning habits can help reduce the spread of respiratory viruses at home, especially when someone in the household is unwell. In most everyday situations, cleaning regularly with soap or detergent is an important first step, and disinfection becomes more important for frequently touched surfaces or when someone sick has recently been in the space.

Focus on high-touch surfaces

Pay extra attention to surfaces that are touched often, such as:

• door handles
• light switches
• taps
• benchtops
• tables
• phones
• remote controls
• keyboards
• bathroom surfaces
• shared equipment or household items

Clean first, then disinfect if needed

A good rule is to clean before you disinfect. Dirt and grime can make it harder for disinfectants to work properly, so surfaces should be cleaned first. In many homes, cleaning alone is often enough for general day-to-day hygiene, but if someone is sick, it is sensible to disinfect surfaces they may have touched, coughed on, or sneezed on.

Keep it practical

When someone in the house has hMPV, COVID-19, flu, or another respiratory illness, helpful habits include:

• cleaning and disinfecting high-touch surfaces more often
• not sharing cups, cutlery, towels, or similar personal items
• washing hands well after cleaning, coughing, sneezing, or handling used tissues
• throwing tissues away straight after use
• cleaning toys or other shared objects if they may be contaminated
• improving airflow indoors where possible

Don’t forget the air around you

Cleaning surfaces matters, but it is only one part of reducing spread. Respiratory viruses can also spread through the air, especially in indoor spaces with poor airflow. That is why it also helps to:

• open windows when appropriate
• increase fresh airflow where possible
• avoid crowded indoor settings when someone is unwell
• keep some distance from others if symptoms are active

Improving indoor air quality can help reduce exposure to respiratory viruses, especially in shared indoor spaces.

Conclusion

Being vigilant about our health and hygiene is of utmost importance, especially in the face of threats like Human Metapneumovirus (hMPV) and other respiratory infections. While we may not have complete control over the presence of such viruses in our environment, we can take proactive steps to protect ourselves and those around us.

Disclaimer: This blog is for general information only and is not a substitute for professional medical advice, diagnosis, or treatment. If you are experiencing symptoms or have concerns about your health, it is important to speak with a qualified healthcare professional. The Aussie Pharma Direct team works hard to provide accurate, up-to-date information and useful content based on reliable sources, reputable health information, and relevant medical research, however, information may change over time and should not be relied on as personal medical advice.

Essentials to Keep on Hand During Respiratory Virus Season