European Programme for Intervention Epidemiology Training, European Centre for Disease Prevention and Control, Stockholm, Sweden.
PLoS Negl Trop Dis. 2013 Aug 15;7(8):e2366. doi: 10.1371/journal.pntd.0002366. eCollection 2013.
During the 2012 cholera outbreak in the Republic of Guinea, the Ministry of Health, supported by Médecins Sans Frontières - Operational Center Geneva, used the oral cholera vaccine Shanchol as a part of the emergency response. The rapid diagnostic test (RDT) Crystal VC, widely used during outbreaks, detects lipopolysaccharide antigens of Vibrio cholerae O1 and O139, both included in Shanchol. In the context of reactive use of a whole-cell cholera vaccine in a region where cholera cases have been reported, it is essential to know what proportion of vaccinated individuals would be reactive to the RDT and for how long after vaccination.
METHODOLOGY/PRINCIPAL FINDINGS: A total of 108 vaccinated individuals, selected systematically among all persons older than one year, were included at vaccination sites and 106 were included in the analysis. Stools samples of this cohort of vaccinated participants were collected and tested with the RDT every day until the test was negative for two consecutive visits or for a maximum of 7 days. A total of 94.3% of cholera vaccine recipients had a positive test after vaccination; all except one of these positive results were reactive only with the O139 antigen. The mean time to become negative in those with an initial positive result after vaccination was 3.8 days, standard deviation 1.1 days.
CONCLUSIONS/SIGNIFICANCE: The RDT Crystal VC becomes positive in persons recently vaccinated against cholera, although almost exclusively to the O139 antigen. This reactivity largely disappeared within five days after vaccination. These results suggest that the test can be used normally as soon as 24 hours after vaccination in a context of O1 epidemics, which represent the vast majority of cases, and after a period of five days in areas where V. cholerae O139 is present. The reason why only O139 test line became positive remains to be investigated.
2012 年，在几内亚共和国爆发的霍乱疫情期间，该国卫生部在无国界医生组织-日内瓦行动中心的支持下，将口服霍乱疫苗 Shanchol 作为应急响应的一部分。在疫情爆发期间广泛使用的快速诊断检测（RDT）Crystal VC 可检测霍乱弧菌 O1 和 O139 的脂多糖抗原，这两种抗原均包含在 Shanchol 中。在报告霍乱病例的地区，有必要在反应性使用全细胞霍乱疫苗的情况下，了解有多少接种个体对 RDT 呈反应性，以及接种后能持续多久。
方法/主要发现：在接种点系统选择了 108 名年龄在 1 岁以上的接种者，对他们进行了研究，其中 106 名被纳入了分析。对这一接种者队列的粪便样本进行采集，并在接种后每天使用 RDT 进行检测，直到连续两次检测均为阴性或最长 7 天。94.3%的霍乱疫苗接种者在接种后 RDT 检测呈阳性；这些阳性结果中除 1 例外，均仅对 O139 抗原呈反应性。接种后初始阳性结果转为阴性的平均时间为 3.8 天，标准偏差为 1.1 天。
结论/意义：在最近接种霍乱疫苗的人群中，RDT Crystal VC 会呈阳性，尽管几乎完全仅对 O139 抗原呈阳性。这种反应性在接种后五天内基本消失。这些结果表明，在 O1 流行的情况下（占绝大多数病例），在接种后 24 小时内可以正常使用该检测，而在存在霍乱弧菌 O139 的地区，则需要五天的时间。仅 O139 检测线呈阳性的原因仍有待调查。
