When I was visiting India this past summer break, I was shocked to discover that the locals were going crazy about a brand-new seasonally emerging virus that had originated out of China. Sound familiar? No, this time it wasn’t COVID-19, but its cousin, the Human Metapneumovirus (HMPV), a viral infection that causes a mild illness like a common cold that can also develop into the upper and lower respiratory illness. Is this the next big threat or a seasonal pest? Although China is obviously desperate to shove this down the memory hole, let us put together what we know to date.
Firstly, HMPV is not just a passing virus but a virus that is out to hurt and kill humankind for a while now. In 2018, an estimated 14.2 million cases of acute lower respiratory tract infections (ALRTIs) associated with hMPV occurred among children under five years of age worldwide (uncertainty range [UR] 10·2 million to 20·1 million). This included approximately 643,000 hospital admissions (UR 425,000 to 977,000), 7700 in-hospital deaths (2600–48 800), and 16100 total ALRTI deaths (5700–88000) in both hospital and community settings. Specifically, HMPV was estimated to cause 11.1 million ALRTI cases (UR 8·0 million to 15·7 million), 502000 hospital admissions (UR 332000 to 762000), and 11300 ALRTI-related deaths (UR 4000 to 61600).
In 2024 alone, it was linked to approximately 11.1 million acute lower respiratory tract infections worldwide, leading to about 502,000 hospital admissions and an estimated 11,300 deaths. Researchers estimate that about 10% to 12% of respiratory illnesses in children are caused by HMPV. HMPV can also cause severe respiratory illness in healthy adults and should be considered as a potential cause of community respiratory outbreaks. Most cases are mild, but about 5% to 16% of children will develop a lower respiratory tract infection like pneumonia. China has seen a notable uptick in HMPV cases since December 2024, with hospitals experiencing overcrowding due to the surge. Fortunately, the prevalence of HMPV cases in Australia is deemed relatively low, with reports indicating that approximately only 7.8% of individuals tested for respiratory pathogens with fever and cough symptoms that were infected with HMPV.
So how much like COVID-19 is this then? Well, firstly both are spread through respiratory droplets, however the HMPV has had a presence in the viral universe for decade compared to the Covid-19. Where the COVID-19 had locked down the entire world due to the ease of transmission of the illness with severe impact, the normal impact of the HMPV was mild illness. On the bright side it seems like we are not going into lockdown again soon. However, like I have mentioned, it can still develop into severe conditions like pneumonia or bronchitis within infants, the very elderly, and the immunocompromised.
But despite all that we must keep it mind that unlike COVID-19, to date there is no vaccine for HMPV. The only way to somewhat prevent it is by maintaining proper hygiene protocols like regular hand washing and avoiding proximity to affected people. Though the crisis is not being experienced in every continent, the impact is significant among vulnerable groups of individuals. The current spike is a reminder of the omnipresence of these sorts of respiratory viruses and the fact that anyone could get sick at any time.
Stay safe!
