Protection conferred by typhoid fever against recurrent typhoid fever in urban kolkata

Justin Im, Md Taufiqul Islam, Deok Ryun Kim, Faisal Ahmmed, Yun Chon, K. Zaman, Ashraful Islam Khan, Mohammad Ali, Dipika Sur, Suman Kanungo, Shanta Dutta, Sujit K. Bhattacharya, Gordon Dougan, Kathryn E. Holt, Florian Marks, Jerome H. Kim, Firdausi Qadri, John D. Clemens

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We evaluated the protection conferred by a first documented visit for clinical care of typhoid fever against recurrent typhoid fever prompting a visit. This study takes advantage of multi-year follow-up of a population with endemic typhoid participating in a cluster-randomized control trial of Vi capsular polysaccharide typhoid vaccine in Kolkata, India. A population of 70,566 individuals, of whom 37,673 were vaccinated with one dose of either Vi vaccine or a control (Hepatitis A) vaccine, were observed for four years. Surveillance detected 315 first typhoid visits, among whom 4 developed subsequent typhoid, 3 due to reinfection, defined using genomic criteria and corresponding to-124% (95% CI:-599, 28) protection by the initial illness. Point estimates of protection conferred by an initial illness were negative or negli-gible in both vaccinated and non-vaccinated subjects, though confidence intervals around the point estimates were wide. These data provide little support for a protective immunizing effect of clinically treated typhoid illness, though modest levels of protection cannot be excluded.

Original languageEnglish (US)
Article numbere0008530
Pages (from-to)1-11
Number of pages11
JournalPLoS neglected tropical diseases
Issue number8
StatePublished - Aug 2020

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Infectious Diseases


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