Efficacy of a locally produced, Chinese Vi polysaccharide typhoid fever vaccine during six years of follow-up.

• Abstract: A locally produced Vi polysaccharide vaccine against typhoid fever was licensed in China following two placebo-controlled, efficacy trials conducted in the early 1990s in Baoying, Jiangsu Province, and Quan-zhou, Guangxi Province. The two trials each enrolled over 80,000 participants and followed participants for 12 and 19 months post-vaccination, respectively. To define the long-term efficacy of this vaccine, we retrospectively assessed the occurrence of typhoid fever, diagnosed with clinical and serological criteria, in the two study populations for 6 years following vaccination. During the second year following vaccination, vaccine efficacy was 100% (95% CI: 17%, 100%) in Baoying and 85% (95% CI: 49%, 96%) in Quan-zhou. There was suggestive protection (51%; PE: -95%, 88%) during the third year in Baoying, nearly identical to the level observed in the third year of an earlier trial in South Africa. These results confirm that this vaccine protects for at least 2 years, and are consistent with the assertion that the vaccine protects for at least 3 years.
• Authors: Camilo J Acosta, Yang Hong-Hui, Wang Ning, Gao Qion, Deng Qun, Ma Xiaolei, Zhou Baode, Wei Liu, M Carolina Danovaro-Holliday, R Leon Ochiai, Xuan-Yi Wang, Deok-Ryun Kim, Xu Zhi-Yi, Dong Bai-Qing, Claudia M Galindo, John D Clemens (Affiliation: International Vaccine Institute, SNU Research Park, San 4-8 Bong-Cheon 7 Dong Kwanak-Ku, Seoul 151-818, South Korea.)
• Journal: Vaccine (Vaccine) Vol. 23 Issue 48-49 Pg. 5618-23 (Dec 1 2005) ISSN: 0264-410X [Print] Netherlands
• PMID: 16098635 (Publication Type: Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antigens, Bacterial
• Polysaccharides, Bacterial
• Typhoid-Paratyphoid Vaccines
• Vi antigen
• Vi polysaccharide vaccine, typhoid

Topics

• Antigens, Bacterial (immunology)
• China
• Follow-Up Studies
• Humans
• Polysaccharides, Bacterial (immunology, therapeutic use)
• Retrospective Studies
• Treatment Outcome
• Typhoid Fever (immunology, microbiology, prevention & control)
• Typhoid-Paratyphoid Vaccines (administration & dosage, immunology, therapeutic use)