Effectiveness of a Typhoid Conjugate Vaccine in DRC

An Open-label Effectiveness Study of a Typhoid Conjugate Vaccine in Kisantu, Democratic Republic of Congo (TyVECO) - Step 2: Typhoid Conjugate Vaccine (TCV) Mass-vaccination Campaign

This is a prospective cohort evaluation of vaccine effectiveness of a single dose of Typbar-TCV® against symptomatic blood culture-confirmed typhoid fever when administered through a mass vaccination campaign to children 9 months to <16 years of age in Kisantu, DRC.

This study is conducted in Kisantu, DRC and is comprised of a mass vaccination campaign of children aged 9 months to <16 years with a single dose of Typbar-TCV® and a concomitant surveillance study to assess the incidence of culture-confirmed typhoid fever in the population during a period of three years following vaccination. Safety events will be monitored for 30 minutes following vaccination for all participants. In a subset of age-eligible participants living in the study area, the investigators will assess local and systemic solicited adverse events/adverse reactions and unsolicited adverse events occurring within the first 7 days post-vaccination and unsolicited and serious adverse events within 28 days post-vaccination. A population census will be conducted at baseline to enumerate and characterize the population under study and demographic information will be collected to allow for minimization of potential sources of bias during analysis. An interim censuses and a census at study closure will be carried out to update population information.

The investigators hypothesize that the Typbar-TCV® vaccine is effective in large scale vaccination campaigns, thereby lowering the incidence of blood-culture confirmed typhoid fever in children. Lessons and experiences on vaccination feasibility and uptake will be important for informing TCV introduction across the African continent.

Inclusion Criteria:

• Parent/guardian willing and able to provide informed consent; assent will be sought for participants between 12 and <16 years of age
• Resident of the defined study area, Kisantu Health Zone at the time of vaccination
• Age between 9 months and <16 years (i.e., ≤15 years and 364 days) on the day of vaccination

Exclusion Criteria:

• The participant has a known allergy to any of the vaccine components,
• Any medical reason perceived to increase risk to health posed by vaccination as judged by a medical professional
• Self-reported pregnancy in females greater or equal to 11 years of age who have reported menarche