Hastings L, Stuart J, Andrews N, Begg N
Public Health Laboratory, Gloucester Royal Hospital.
Commun Dis Rep CDR Rev. 1997 Dec 12;7(13):R195-200.
Information about the epidemiology of meningococcal disease case clusters and the risk of further cases is sparse. Data on clusters in household and educational settings from 1 January 1993 to 31 March 1995 was requested from consultants in communicable disease control in England and Wales through a retrospective postal survey. Ninety-three per cent (122/131) responded. Of the 114 cases in 45 reported clusters, 77 (67.5%) were microbiologically confirmed. The case fatality rate in index cases was higher than in associated cases (18.2% vs 4.5%; p = 0.02). Five out of 11 clusters in household settings consisted only of index and co-primary cases. No further cases occurred within two weeks after giving chemoprophylaxis to household contacts. The relative risks of further cases in the week after the index case arose were estimated to be 1200 for contacts in the household, 160 in secondary schools, 60 in primary schools, 1.8 in universities/colleges, and 0 in nurseries. Between seven and 30 days the relative risks were lower; 150 in households, and between 0 and 13 in all other settings. Beyond 30 days, the relative risk in the household setting was 8 and lower than this in all other settings. The absolute risk of further cases in the month following the index case was calculated as 210 per 100,000 in household members, 7-10/10(5) in pupils at the same school, and 0.6/10(5) in students at the same university or college. The current policy in England and Wales to recommend chemoprophylaxis for household members may prevent half of the further cases in this setting. Raised awareness may have contributed to the lower case fatality rate among household contacts who developed meningococcal disease, but the number of co-primary cases observed should prompt urgent enquiries about current illness in household contacts of index cases. The relative risk of further cases in preschool groups was low and apparently unaffected by changes in chemoprophylactic policy. The relative risk in school settings was raised in the month following a case, but the absolute risk was still low. Further study to quantify the risk in university settings is needed.
关于脑膜炎球菌病病例聚集的流行病学以及后续病例风险的信息非常稀少。通过一项回顾性邮政调查，向英格兰和威尔士传染病控制顾问索取了1993年1月1日至1995年3月31日期间家庭和教育场所聚集病例的数据。93%（122/131）做出了回应。在45个报告的聚集病例中的114例中，77例（67.5%）经微生物学确诊。首例病例的病死率高于相关病例（18.2%对4.5%；p = 0.02）。家庭环境中的11个聚集病例中有5个仅由首例病例和共同首例病例组成。对家庭接触者进行化学预防后两周内未出现更多病例。首例病例出现后一周内，家庭接触者、中学接触者、小学接触者、大学/学院接触者以及托儿所接触者出现更多病例的相对风险估计分别为1200、160、60、1.8和0。在7至30天之间，相对风险较低；家庭中为150，其他所有场所为0至13。超过30天，家庭环境中的相对风险为8，低于其他所有场所。首例病例后一个月内出现更多病例的绝对风险计算为：家庭成员每10万人中210例，同一学校学生中7 - 10/10（5）例，同一大学或学院学生中0.6/10（5）例。英格兰和威尔士目前建议对家庭成员进行化学预防的政策可能会预防该环境中一半的后续病例。意识提高可能有助于降低患脑膜炎球菌病的家庭接触者的病死率，但观察到的共同首例病例数量应促使对首例病例的家庭接触者当前疾病情况进行紧急调查。学龄前儿童组出现更多病例的相对风险较低，且显然不受化学预防政策变化的影响。病例出现后的一个月内，学校环境中的相对风险有所升高，但绝对风险仍然较低。需要进一步研究以量化大学环境中的风险。
