The rate of infections with the flu-like human metapneumovirus (HMPV) in northern China is declining, a health official said, amid some international concern over a potential pandemic. HMPV causes flu or cold-like symptoms including fever, cough and nasal congestion. The symptoms usually clear up by themselves, though they can cause lower respiratory tract infections among children, older adults and those immunocompromised. A researcher at the Chinese Center for Disease Control and Prevention said during a press briefing Sunday that the virus is not new. Concerns surfaced in recent days over a surge in HMPV infections in northern China after images circulated online of hospitals overrun with masked patients.