Nokes D James, Okiro Emelda A, Ngama Mwanajuma, Ochola Rachel, White Lisa J, Scott Paul D, English Michael, Cane Patricia A, Medley Graham F
Kenya Medical Research Institute, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya.
Clin Infect Dis. 2008 Jan 1;46(1):50-7. doi: 10.1086/524019.
In developing countries, there are few data that characterize the disease burden attributable to respiratory syncytial virus (RSV) and clearly define which age group to target for vaccine intervention.
Six hundred thirty-five children, recruited during the period 2002-2003, were intensively monitored until each experienced 3 epidemics of RSV infection. RSV infection was diagnosed using immunofluorescence of nasal washing specimens collected at each episode of acute respiratory infection. Incidence estimates were adjusted for seasonality of RSV exposure.
For 1187 child-years of observation (CYO), a total of 409 (365 primary and 82 repeat) episodes of RSV infection were identified. Adjusted incidence estimates of lower respiratory tract infection (LRTI), severe LRTI, and hospital admission were 90 cases per 1000 CYO, 43 cases per 1000 CYO, and 10 cases per 1000 CYO, respectively, and corresponding estimates among infants were 104 cases per 1000 CYO, 66 cases per 1000 CYO, and 13 cases per 1000 CYO, respectively. The proportion of cases of all-cause LRTI, and severe LRTI and hospitalizations attributable to RSV in the cohort was 13%, 19%, and 5%, respectively. Fifty-five percent to 65% of RSV-associated LRTI and severe LRTI occurred in children aged >6 months. The risk of RSV disease following primary symptomatic infection remained significant beyond the first year of life, and one-quarter of all reinfections were associated with LRTI.
RSV accounts for a substantial proportion of the total respiratory disease in this rural population; we estimate that 85,000 cases of severe LRTI per year occur in infants in Kenya. The majority of this morbidity occurs during late infancy and early childhood--ages at which the risk of disease following infection remains significant. Disease resulting from reinfection is common. Our results inform the debate on the target age group and effectiveness of a vaccine.
在发展中国家，关于呼吸道合胞病毒（RSV）所致疾病负担的数据很少，并且对于疫苗干预的目标年龄组没有明确界定。
在2002年至2003年期间招募了635名儿童，对他们进行密切监测，直到每人经历3次RSV感染流行。RSV感染通过在每次急性呼吸道感染发作时采集的鼻腔冲洗标本的免疫荧光检测来诊断。发病率估计值针对RSV暴露的季节性进行了调整。
在1187个儿童年观察期（CYO）内，共识别出409次（365次初次感染和82次再次感染）RSV感染发作。下呼吸道感染（LRTI）、严重LRTI和住院的调整发病率估计值分别为每1000个CYO中有90例、每1000个CYO中有43例和每1000个CYO中有10例，婴儿中的相应估计值分别为每1000个CYO中有104例、每1000个CYO中有66例和每1000个CYO中有13例。该队列中所有原因导致的LRTI、严重LRTI以及住院病例中归因于RSV的比例分别为13%、19%和5%。55%至65%的RSV相关LRTI和严重LRTI发生在年龄大于6个月的儿童中。初次有症状感染后RSV疾病的风险在生命的第一年之后仍然很高，并且所有再次感染中有四分之一与LRTI相关。
RSV在该农村人群的全部呼吸道疾病中占很大比例；我们估计肯尼亚每年有85000例婴儿发生严重LRTI。这种发病情况大多数发生在婴儿晚期和幼儿期——这些年龄段感染后患病风险仍然很高。再次感染导致的疾病很常见。我们的结果为关于疫苗目标年龄组和有效性的辩论提供了信息。
