Department of Tropical Pediatrics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
PLoS Negl Trop Dis. 2012;6(7):e1732. doi: 10.1371/journal.pntd.0001732. Epub 2012 Jul 31.
There is an urgent need to field test dengue vaccines to determine their role in the control of the disease. Our aims were to study dengue epidemiology and prepare the site for a dengue vaccine efficacy trial.
We performed a prospective cohort study of children in primary schools in central Thailand from 2006 through 2009. We assessed the epidemiology of dengue by active fever surveillance for acute febrile illness as detected by school absenteeism and telephone contact of parents, and dengue diagnostic testing. Dengue accounted for 394 (6.74%) of the 5,842 febrile cases identified in 2882, 3104, 2717 and 2312 student person-years over the four years, respectively. Dengue incidence was 1.77% in 2006, 3.58% in 2007, 5.74% in 2008 and 3.29% in 2009. Mean dengue incidence over the 4 years was 3.6%. Dengue virus (DENV) types were determined in 333 (84.5%) of positive specimens; DENV serotype 1 (DENV-1) was the most common (43%), followed by DENV-2 (29%), DENV-3 (20%) and DENV-4 (8%). Disease severity ranged from dengue hemorrhagic fever (DHF) in 42 (10.5%) cases, dengue fever (DF) in 142 (35.5%) cases and undifferentiated fever (UF) in 210 (52.5%) cases. All four DENV serotypes were involved in all disease severity. A majority of cases had secondary DENV infection, 95% in DHF, 88.7% in DF and 81.9% in UF. Two DHF (0.5%) cases had primary DENV-3 infection.
The results illustrate the high incidence of dengue with all four DENV serotypes in primary school children, with approximately 50% of disease manifesting as mild clinical symptoms of UF, not meeting the 1997 WHO criteria for dengue. Severe disease (DHF) occurred in one tenth of cases. Data of this type are required for clinical trials to evaluate the efficacy of dengue vaccines in large scale clinical trials.
迫切需要进行登革热疫苗的现场测试，以确定其在疾病控制中的作用。我们的目的是研究登革热流行病学，并为登革热疫苗功效试验做准备。
我们对泰国中部的小学生进行了一项前瞻性队列研究，从 2006 年至 2009 年进行了研究。通过因缺课而被学校发现的发热儿童和通过电话联系家长的方式主动监测急性发热疾病，对登革热进行了流行病学评估，并进行了登革热诊断检测。在 2882、3104、2717 和 2312 名学生的 2882、3104、2717 和 2312 个学生年中，登革热分别占 394 例（6.74%）发热病例。2006 年、2007 年、2008 年和 2009 年的登革热发病率分别为 1.77%、3.58%、5.74%和 3.29%。4 年来的平均登革热发病率为 3.6%。在 333 份阳性标本中确定了登革热病毒（DENV）类型；DENV 血清型 1（DENV-1）最为常见（43%），其次是 DENV-2（29%）、DENV-3（20%）和 DENV-4（8%）。疾病严重程度从登革出血热（DHF）的 42 例（10.5%）、登革热（DF）的 142 例（35.5%）和未分化发热（UF）的 210 例（52.5%）不等。所有 4 种 DENV 血清型均与所有疾病严重程度有关。大多数病例为二次 DENV 感染，DHF 中为 95%，DF 中为 88.7%，UF 中为 81.9%。2 例 DHF（0.5%）患者发生原发性 DENV-3 感染。
结果表明，4 种 DENV 血清型在小学生中均有较高的登革热发病率，约 50%的疾病表现为 UF 等轻微临床症状，不符合 1997 年世卫组织的登革热标准。十分之一的病例发生严重疾病（DHF）。此类数据是在大规模临床试验中评估登革热疫苗疗效的临床试验所必需的。
