Respiratory Virus That Lacks Vaccine Spreads in US

A respiratory virus with no vaccine or specific treatment is appearing in parts of the United States, including California and New Jersey. The virus, known as human metapneumovirus (HMPV), can infect both the upper and lower respiratory tract, according to the Centers for Disease Control and Prevention. Treatment is mainly focused on relieving symptoms rather than targeting the virus itself.

Most people who get HMPV recover without needing medical care. Health officials recommend rest, drinking plenty of fluids, and staying home while sick to prevent spreading the illness. In more serious cases—such as when breathing becomes difficult—oxygen therapy may be used, according to the Cleveland Clinic.

HMPV was first identified in 2001 and last saw a noticeable surge in the United States in April 2025. Federal surveillance data shows that as of Feb. 21, the virus accounted for just over 5% of weekly positive respiratory virus tests, up from 3.83% the previous week. The peak in April 2025 reached 7.43%. Cases have been rising since October, with elevated levels reported in the San Francisco Bay Area, Napa Valley, and parts of the Northeast. China has also recently experienced increased activity from the virus.

Despite the rise in cases, health officials say there is no major cause for alarm. According to the Mayo Clinic, nearly everyone will contract some strain of HMPV at least once in their lifetime. Symptoms typically include cough, nasal congestion, fever, and shortness of breath. In some cases, the illness can develop into bronchitis or pneumonia.

Like the flu, HMPV tends to circulate from winter into spring, with an incubation period of about three to six days. Young children and adults age 65 and older face the highest risk of severe illness.

Health experts recommend common preventive steps to reduce the spread of respiratory viruses. These include washing hands frequently, avoiding touching the face with unwashed hands, staying away from people who are sick, cleaning frequently touched surfaces, improving indoor air quality when possible, and covering coughs and sneezes.