Reports of a respiratory virus spreading in China and scenes of packed hospitals have sparked fear, with worries that the human metapneumovirus (HMPV) could become the COVID 2.0 of 2025.

In the US, cases have been on the rise since November, although the overall numbers remain low. The CDC reported that 1.94% or 13,800 individuals tested positive for HMPV in the week of Dec. 28.

However, health experts say the rise in cases is not necessarily cause for alarm, maintaining that HMPV is a very different type of illness.

Virology Professor Jill Carr from Flinders University stated to SBS News that the surge in HMPV cases in China should not be equated to the previous pandemic.

“HMPV can certainly make people very sick, and high case numbers are a threat to effective hospital services, but the current situation in China with high HMPV cases is very different to the threats initially posed by SARS-CoV-2 resulting in the COVID-19 pandemic,” she said.

Amesh Adalja, an infectious-diseases physician and senior scholar at the Johns Hopkins Center for Health Security, maintains that any big reaction to HMPV is just a knee-jerk response.

“There’s just this tendency post-COVID to treat every infectious-disease anything as an emergency when it’s not,” Adalja told The Washington Post. “You wouldn’t probably be calling me in 2018 about this.”

The CDC said it was aware of increasing HMPV cases in northern China following reports from Beijing-run media confirming positivity rates have risen significantly among children 14 and younger.

However, it stressed that the number of respiratory disease cases in America remains at “pre-pandemic” levels and is not a cause for concern.

And in a statement released on Friday, the Chinese government downplayed claims that HMPV cases were skyrocketing.

“Respiratory infections tend to peak during the winter season,” the Chinese Foreign Ministry said. “The diseases appear to be less severe and spread with a smaller scale compared to the previous year,” the office added.

Sanjaya Senanayake, an associate professor of medicine at the Australian National University, told SBS News, “At this stage, the likelihood is that China is experiencing a bad HMPV season, in the same way that in some years we have an overwhelming flu season. This could be due to a combination of viral and behavioral factors, but it should settle down.”

What is HMPV?

HMPV is a respiratory disease that causes symptoms much like the common cold or flu: cough, fever, congestion, runny nose, a sore throat, and shortness of breath, according to the Cleveland Clinic.

Unlike COVID, HMPV is considered an “anonymous virus,” meaning many people infected with HMPV don’t know that they have it, dismissing their symptoms as cold or flu. However, MPV can progress to more dire symptoms, including pneumonia.

Among young children, older adults, and the immunocompromised, HMPV can cause an illness severe enough to send them to the hospital.

Most children have had HMPV by the time they reach the age of 5 and quickly recover, but for some youngsters, the disease can take a troubling turn.

A 2015 study in the Journal of the Pediatric Infectious Diseases Society found that babies and children younger than 2 years old were most likely to be hospitalized with HMPV. Of these, 18% were treated in the intensive care unit, while 6% required mechanical ventilation due to breathing difficulties.

A study published in the Lancet estimated that in 2018, HMPV caused 643,000 hospital admissions and 16,100 deaths worldwide among children younger than 5.

Also unlike COVID, HMPV has been around for decades. Carr, the virologist at Flinders University, explained that with the outbreak of COVID-19, “the virus was completely new in humans and arose from a spill-over from animals and spread to pandemic levels because there was no prior exposures or protective immunity in the community.”

HMPV, which belongs to the same virus family as respiratory syncytial virus (RSV), is believed to have originated in an avian species centuries ago but was not discovered until 2021.

However, as CNN reported, an analysis of blood samples from the 1950s suggests the virus has been circulating among humans for at least half a century.

Cases typically rise in January, peak in March and April, then drop as the weather warms in May. According to experts, the severity of HMPV cases varies annually.

The jump in US cases of HMPV in 2023 might have been due to people having less immunity after years of mask-wearing and social distancing during the COVID-19 pandemic.

Similarly, experts posit that China’s prolonged COVID lockdown markedly reduced exposure to HMPV, presumably making people more susceptible to infection during the recent surge.

Most people with an HMPV infection get better after a few days of rest, fluid intake, and over-the-counter decongestants and pain medicine.

There’s currently no cure or vaccine for HMVP.

Doctors recommend the usual precautions against HMPV and other respiratory viruses: washing your hands regularly, avoiding people who are ill, and staying home if you feel sick.