Interesting Facts About Human Metapneumovirus (Hmpv)

Introduction

Hospitals across China are currently grappling with a surge of patients battling Human Metapneumovirus (hMPV). The situation, as depicted in viral social media posts showing overcrowded wards and masked elderly patients, has sparked widespread concern and revived memories of the COVID-19 chaos. This urgent situation demands our attention.

HMPV is a respiratory virus that exhibits symptoms similar to the common cold but can also lead to severe respiratory illnesses in vulnerable populations.

The number of cases in China, Malaysia, India, and Kazakhstan has been rising recently despite being discovered in 2001. The recent spike has contributed to the ongoing winter season and immune debt caused by extra precautions taken during the COVID-19 pandemic.

The fresh wave of hMPV cases was first reported in mid-December 2024 in China. The infection outbreak was first brought to public attention through a viral social media post. The video shows an overcrowded hospital filled with elderly patients sitting with masks. The video has garnered 12 million views and refreshed COVID-19 chaos memories among the masses. In another video from China, a hospital waiting room is filled with coughing patients. These videos have created a panic among people. 

Commenting on the spread of hMPV, Mao Ning, the spokesperson for the Chinese foreign ministry, said that such infections are, although expected to rise, the current situation is under control. It is less severe than in previous years. 

In addition to China, hMPV cases have also been reported in Kazakhstan, Malaysia, and India.

Despite rising cases in different nations, health officials have been reassured that the virus poses a threat similar to the COVID-19 pandemic because it has been present in the population since 2001.

A Relative Newcomer with Old Roots:

hMPV was discovered in the Netherlands in 2001. On its identification, scientists found that the virus had already been present in human immune systems for more than 50 years. It suggests that the virus went undiagnosed for several decades, if not centuries because its symptoms are almost identical to those of more common respiratory infections such as the common cold.

Contrary to popular belief, hMPV is not a rare occurrence. In fact, it's more common than you might think. This knowledge can help us stay informed and aware of potential health risks.

As noted earlier, the virus has been discovered two decades ago. Since then, hMPV has accounted for around 5-10% of all hospitalizations linked to acute respiratory infections in children and the elderly during peak seasons in the US. 

Surprisingly, the virus is as prevalent as other common viruses but goes unnoticed.

Same-same but different:

hMPV is closely related to its sibling, Respiratory Syncytial Virus (RSV). Both viruses belong to the Paramyxoviridae family, but hMPV is slightly different in its genetic makeup. Scientists also refer to it as the "Silent troublemaker". The virus generally attacks in a seasonal pattern each year, usually in late winter and spring.

hMPV does not have a Vaccine or Targeted Antiviral.

Unlike flu or COVID-19, there is currently no vaccine for hMPV.

In some cases, doctors might treat its associated symptoms like pneumonia, but no one targeted vaccine for the infection exists. Prevention and early detection, hence, are very crucial for timely treatment in high-risk groups.

hMPV came From Bird Flu:

hMPV’s avian relatives (like AMPV) can cause significant economic losses in the poultry industry. Scientists believe that the disease has evolved from Bird Flu, and the virus has since evolved to infect humans as well.

In chickens and turkeys, the virus causes an infection that affects their health and egg production. Studying hMPV helps us understand its impact on both human and animal health.

Unusual hMPV Infection Surges in 2023-24:

After COVID-19 limitations were lifted in 2022, there were reports of a more severe flu season. Hospitals in Australia and the United States reported more flu cases than predicted. Scientists have reported that it is partly because people's immunity dropped due to non-exposure to flu-causing viruses for prolonged periods.

It is known as immune debt, a syndrome produced by decreased exposure to seasonal viruses during the COVID-19 pandemic.

During the pandemic, people were more cautious, wore masks, and maintained social distancing. Hence, they were exposed to fewer viruses than usual. So, when pandemic restrictions were lifted, people began interacting more in public again. However, our immune systems hadn't been 'primed' as much due to lack of exposure to these viruses over the previous years. So, after distancing and mask-wearing relaxed, hMPV began spreading more widely again.

This is evident in the graph attached below (Refer to graphs).

Graph 1: Rise in the number of hMPV cases in Western Australia (2017-2023)

Source: mdpi.com

Graph 2: Rise in the number of hMPV cases (2019-2021) 

Source: (mdpi.com, 2022)

As evident in the graphs, hMPV, which had previously caused sporadic outbreaks, began to spread more widely in 2023 and 2024 after pandemic restrictions eased. The number of tests conducted and reported cases rose in the past three years.

Conclusion

hMPV is not new. It has been infecting people for decades. However, due to the lack of a vaccine, prevention and early detection of the disease becomes imperative. 

That being said, doctors have stated against the dangers of the virus, stating that the virus is not new; humans have already built immunity to the virus. The virus is hazardous for high-risk groups. Maintaining good hygiene, washing hands regularly, wearing a mask, and preventing contact with people experiencing cold-like symptoms are advised.