This Virus is Spreading Like Wildfire in China—What is HMPV and Why Is It Spreading So Fast?

The human metapneumovirus (HMPV), a respiratory infection, is spreading rapidly across China.

Local Chinese media reported a surge in HMPV cases since mid-December. This virus can cause illnesses in the upper and lower respiratory tracts. On the same day, the Indian government confirmed its first case of infection.

HMPV was first identified in 2001. It primarily affects infants and causes acute respiratory symptoms such as pneumonia and fever. The U.S. Centers for Disease Control and Prevention (CDC) states that the virus has an incubation period of three to six days. Symptoms include cough, nasal congestion, fever, and difficulty breathing. These symptoms closely resemble those of influenza, making diagnosis challenging.

Children and adults over 65 are at the highest risk of HMPV progressing to bronchitis or pneumonia. The virus spreads through respiratory droplets from coughs and sneezes, close personal contact, and touching contaminated surfaces before touching one’s face.

Currently, there is no vaccine for HMPV. Prevention methods mirror those used for COVID-19 and other respiratory infections: wearing masks, frequent handwashing, and maintaining good personal hygiene. No specific antiviral treatments exist; doctors manage severe cases by treating symptoms.

Co-infections of HMPV with pneumococcus, influenza, or respiratory syncytial virus (RSV) can lead to more severe outcomes. Experts recommend vaccinating against other respiratory diseases when possible to reduce overall risk.

The CDC reports a steady increase in HMPV cases in the U.S. since November last year. As of December 28, the weekly positive rate for HMPV tests reached 1.94%. While lower than the flu (18.71%) and COVID-19 (7.10%) rates for the same period, HMPV cases are on an upward trend.

Chinese experts emphasize that HMPV is not a new threat but a globally widespread virus. Although it has existed for six decades, its slow spread and often mild symptoms led to its official identification only in 2001.

The rising case numbers in China have led to increased hospitalizations. Analysts attribute this surge to decreased HMPV exposure during the COVID-19 pandemic, which may have weakened community immunity.

India confirmed five HMPV cases on Sunday. Two infants in Bengaluru, Karnataka–a three-month-old girl and an eight-month-old boy–tested positive, along with three other cases in different regions.