title: Seroepidemiology of Enterovirus 71 infection prior to the 2011 season in children in Shanghai.
abstract: BACKGROUND
  In 2010, China experienced the largest outbreak on record of Enterovirus 71 (EV71)-associated Hand Foot and Mouth Disease (HFMD) with more than 1.7 million cases, 27,000 patients with severe neurological complications and 905 deaths. Understanding of the seroprevalence of neutralizing antibodies (NAb) against EV71 and their protective role against HFMD in children is crucial for the implementation of future therapeutic and prophylactic intervention.
  
  
  OBJECTIVE
  To correlate the prevalence of NAb against EV71 genotype C4a in children prior to the 2011 epidemic season with severe EV71-associated HFMD disease during the subsequent 2011 epidemic season.
  
  
  METHODS
  614 sera samples were collected from children without HFMD. EV71 NAb were tested by a quantitative PCR assay. Samples with NAb ≥1:8 were scored as positive.
  
  
  RESULTS
  122 (19.9%) of 614 sera were EV71-seropositive. The NAb seroprevalence was highest in infants 0-5 months of age (28.6%) and lowest in children 1-1.9 years of age (13.4%). 64.1% of severe EV71-associated HFMD occurred in children 1-2.9 years.
  
  
  CONCLUSIONS
  Despite the large 2010 outbreak, the overall seroprevalence of EV71 in children is relatively low. The seropositive rate of EV71 NAb prior to the 2011 season was inversely correlated with the number of EV71-infected severe cases in 2011. Loss of maternal antibodies in infants and lack of acquired anti-EV71 immunity are responsible for increased proportion of severe HFMD in the 1-2 years age group. Our data suggest that future vaccination campaigns should be initiated as early as 6 months.
authors.affiliation: Department of Infectious Diseases, Children's Hospital of Fudan University, Shanghai 201102, China.
authors.forename: Mei
authors.initials: M
authors.lastname: Zeng
authors.forename: Névine Fahmy
authors.initials: NF
authors.lastname: El Khatib
authors.forename: Shuyang
authors.initials: S
authors.lastname: Tu
authors.forename: Peijun
authors.initials: P
authors.lastname: Ren
authors.forename: Shanshan
authors.initials: S
authors.lastname: Xu
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Zhu
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Mo
authors.forename: Dongbo
authors.initials: D
authors.lastname: Pu
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Wang
authors.forename: Ralf
authors.initials: R
authors.lastname: Altmeyer
mesh_terms: D057134:Antibodies, Neutralizing / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D004196:Disease Outbreaks; D029821:Enterovirus A, Human / Q000145:classification / Q000235:genetics / Q000276:immunology*; D004769:Enterovirus Infections / Q000453:epidemiology* / Q000821:virology*; D058872:Epidemics; D006232:Hand, Foot and Mouth Disease / Q000453:epidemiology* / Q000821:virology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D012621:Seasons; D016036:Seroepidemiologic Studies
chemical_list: D057134:Antibodies, Neutralizing