High seroprevalence of human metapneumovirus among young children in Israel.

Exposure to the newly discovered human metapneumovirus (HMPV) during the first 2 years of life was studied by longitudinal serological analysis in 40 healthy children in southern Israel. The seropositivity rate decreased to a minimum by age 13 months and increased to 52% by age 24 months. Evidence of new infection was detected in 13%, 23%, and 55% of children by ages 7, 13, and 24 months, respectively. The high exposure rates suggest that HMPV may be an important cause of community-acquired respiratory-tract infections in young children.