OBJECTIVETo investigate the main factors that influence measles morbidity and the genotype of measles virus, so as to provide evidence for scientific decision making to further control the prevalence of measles.

METHODA retrospective analysis included 182 children in Children's Hospital of Fudan University, diagnosed with measles from January 1, 2012 to December 31. The clinical and epidemiological characteristics, including the gender, age, the incidence of seasonal trends, measles vaccine vaccination history, contact history and other clinical manifestations, laboratory test results, and so on were analyzed. And the reverse transcription PCR (RT-PCR) was adopted to detect sputum specimens from suspected patients with measles,who were selected randomly,the sequence of the part of the PCR products was analyzed.

RESULT(1) Clinical and epidemiological data: Totally were 182 children with measles (125 males, 57 females) were enrolled into this study. The age of the patients ranged from 3 months to 89 months, 127 cases were younger than 9 months (69. 8%). The prevalence season was from April to August, while the peak month was April and May (22. 5%, 23. 1%). Among 182 hospitalized children, only 11 cases underwent measles vaccination (6. 0%), and among them 5 cases were within 2 weeks before disease onset. A total of 167 cases (91. 8%) had not been vaccinated, most of whom were immigrants, and the measles vaccination history of the remaining 4 cases were unknown. There was a positive correlation between the measles vaccination ratio in children of the floating population (8. 45%, 6/71) and the settled children (29.4%, 5/17, χ =8. 11 P =0. 004). In total, 24 cases (13. 2%) had definite measles exposure history, with 153 cases (84. 1%) of unknown origin,5 cases (2.7%) without any history of contact. (2) Clinical manifestations: All the 182 patients had fever (100%) and obvious rashes (100%), among them 145 cases had body temperature higher than 39 °C (79. 7%). The fever period ranged from 2 to 38 days. Among 182 hospitalized children,165 cases (90. 7%) had typical measles,17 cases had atypical measles. Among the 17 cases, two had severe measles, one had heterotypic measles. (3) The common complica tions: 96 cases had pneumonia (52. 8%), 80 had laryngitis (44. 0%), 38 had bronchitis (20. 9%),15 had hepatic dysfunction (8. 2%), 11 had myocardial damage (6. 0%), 3 had febrile seizures (1. 6%), and no patient had encephalitis. Of the 96 cases with pneumonia, 92 received sputum test; 38 were sputum culture positive (41%). The dominant pathogens were Streptococcus pneumoniae(11/38,29%), Haemophilus influenzae (6/ 38,16%), Moraxella catarrhalis (4/38, 11%), Escherichia coli (4/38, 11%), Candida albicans (4/38, 11%), Mycoplasma pneumoniae (4/38, 11%) and Staphylococcus aureus (3/38, 8%). (4) The H1a genotype was the only one genotype in the detected sequence of 54 measles virus strains.

CONCLUSIONMeasles was more often seen in the children under the age of 9 months from the floating population. The morbidity peak month was from April to May in Shanghai. The H1a genotype was the only one genotype. We should try to improve vaccination coverage rate in the children who are at the age for vaccination, so as to prevent measles outbreak.