How worried should Kenyans be about HMPV outbreak in China?

Dr Ahmed Kalebi.

Unlike Covid-19, which took the world by storm in 2020, hMPV has been around for more than two decades and is now a common respiratory virus worldwide.

Dr Ahmed Kalebi, pathologist and CEO of Dr Kalebi Labs in Nairobi, says hMPV is not new. “This virus has been in circulation since 2001 and is now part of seasonal flu viruses around the world,” he explains. “Unlike SARS-CoV-2, which was a novel and highly virulent virus, most people have been exposed to hMPV by the time they turn five years old. This gives them natural immunity.”

Human metapneumovirus was first identified in 2001 by Dutch researchers. It belongs to the same family as respiratory syncytial virus (RSV) and primarily causes respiratory tract infections.

The virus is common among children under five and older adults. In healthy individuals, hMPV typically causes mild symptoms similar to a cold or flu, such as fever, cough, nasal congestion, and fatigue.

However, Kalebi says severe cases can occur. These are most common in infants, the elderly, and immunocompromised individuals. “Severe illness can include pneumonia or acute respiratory distress,” he told The Star. Infants under one year are particularly vulnerable, accounting for up to 74 per cent of hMPV cases.

The outbreak in China has drawn attention because of its timing and the increase in reported cases. But Dr Kalebi emphasises that this uptick is not unusual. “HMPV and RSV tend to have peak transmission during certain times of the year. The rise in cases likely coincides with seasonal patterns,” he says. Seasonal peaks for hMPV typically occur during cooler months or periods of low humidity.

Dr Kalebi cautions against linking the rise in hMPV cases in China to the possibility of a new pandemic. “There is no need to worry about hMPV to the extent of Covid-19,” he says. “Most people have already been exposed to it, and herd immunity exists globally.”

For those concerned about potential hMPV infections, advanced testing options are available. Multiplex PCR tests, which detect multiple respiratory viruses, including hMPV, RSV, influenza, and SARS-CoV-2, are the gold standard. Kalebi points out that these tests can confirm the presence of hMPV using respiratory samples, such as throat swabs, with quick turnaround times.

At his lab, hMPV can be tested within two hours. “We offer multiplex PCR testing for hMPV and other respiratory viruses. It’s accessible to walk-in patients and referred samples,” he notes. Rapid antigen tests for hMPV exist but are not widely used or validated for regular diagnostic purposes in most countries, including Kenya.

No Vaccines, No Panic