Determining the Best Immunization Strategy for Protecting African Children Against Invasive Salmonella Disease

Clin Infect Dis. 2018 Nov 28;67(12):1824-1830. doi: 10.1093/cid/ciy386.


Background: The World Health Organization recently prequalified a typhoid conjugate vaccine (TCV), recommending its use in persons ≥6 months to 45 years residing in typhoid fever (TF)-endemic areas. We now need to consider how TCVs can have the greatest impact in the most vulnerable populations.

Methods: The Typhoid Fever Surveillance in Africa Program (TSAP) was a blood culture-based surveillance of febrile patients from defined populations presenting at healthcare facilities in 10 African countries. TF and invasive non-typhoidal Salmonella (iNTS) disease incidences were estimated for 0-10 year-olds in one-year age increments.

Results: Salmonella Typhi and iNTS were the most frequently isolated pathogens; 135 and 94 cases were identified, respectively. Analysis from three countries was excluded (incomplete person-years of observation (PYO) data). Thirty-seven of 123 TF cases (30.1%) and 71/90 iNTS disease cases (78.9%) occurred in children aged <5 years. No TF and 8/90 iNTS infections (8.9%) were observed in infants aged <9 months. The TF incidences (/100 000 PYO) for children aged <1 year and 1 to <2 years were 5 and 39, respectively; the highest incidence was 304 per 100 000 PYO in 4 to <5 year-olds. The iNTS disease incidence in the defined age groups ranged between 81 and 233 per 100 000 PYO, highest in 1 to <2 year-olds. TF and iNTS disease incidences were higher in West Africa.

Conclusions: High burden of TF detected in young children strengthens the need for TCV introduction. Given the concurrent iNTS disease burden, development of a trivalent vaccine against S. Typhi, S. Typhimurium, and S. Enteritidis may be timely in this region.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Africa South of the Sahara / epidemiology
  • Child
  • Child, Preschool
  • Cost of Illness
  • Epidemiological Monitoring
  • Fever / epidemiology
  • Fever / microbiology*
  • Humans
  • Incidence
  • Infant
  • Infant, Newborn
  • Salmonella / isolation & purification
  • Salmonella Infections / epidemiology*
  • Salmonella Infections / prevention & control
  • Salmonella typhi / isolation & purification
  • Typhoid-Paratyphoid Vaccines / therapeutic use
  • Vaccines, Conjugate / therapeutic use
  • Young Adult


  • Typhoid-Paratyphoid Vaccines
  • Vaccines, Conjugate