Abstract: Objective To investigate the outbreak of human metapneumovirus infection in a primary school in Hai Dian,analyze the epidemic characteristics and influencing factors,and provide basis for the prevention and control of this kind of virus infection.Methods Field epidemiological investigation and individual survey were conducted. Throat swabs samples were collected for detection the respiratory tract multi pathogenic nucleic acids.Results There were 16 cases of human metapneumovirus infection in the school and all of them were students. The total attack rate was 38. 10% (16/42),and there was no significant difference between different genders (χ²= 2. 041,P= 0. 153). The positive rate of human metapneumovirus nucleic acid was 85. 71% (6/7),and other respiratory multi pathogenic nucleic acids were negative. The cases were concentrated in class 7,grade 1,and the onset time was from November 29 to December 3. The latent period was 2-4 days. The main clinical symptoms were fever and cough,accounting for 100%and 87. 50% respectively. The shortest fever time was 3 days and the longest was 8 days,with an average of (4. 19 ± 1. 16) days.Conclusions Human metapneumovirus is highly infectious. The latent period is short. Fever and cough are the main symptoms and the fever period is about 3. 03-5. 35 days. There is no specific treatment and vaccine. All of these make the prevention and control work face a severe test,and it is urgent to improve the knowledge reserve of prevention and control personnel.