Publications by authors named "Theresa Misiri"

Article Synopsis
  • Vaccine safety and immunogenicity data are crucial for making informed decisions in countries where both HIV and typhoid are prevalent, specifically focusing on HIV-exposed uninfected (HEU) children.
  • In a study involving Malawian infants, HEU and HIV unexposed uninfected (HUU) participants received the Vi-tetanus toxoid conjugate vaccine (Vi-TT) at different ages, with safety and immune response monitored after vaccination.
  • Results showed that the vaccine was generally safe with mild adverse events, and both HEU and HUU children had strong immune responses, indicating that a single dose of Vi-TT could be effectively introduced in HIV-endemic regions.
View Article and Find Full Text PDF

Background: Non-typhoidal Salmonella (NTS) are a major cause of bloodstream infections amongst children in sub-Saharan Africa. A clear understanding of the seroepidemiology and correlates of protection for invasive NTS (iNTS) in relation to key risk factors (malaria, anaemia, malnutrition) in children in Africa is needed to inform strategies for disease control including vaccine implementation.

Methodology: The SAiNTS study is a prospective community cohort study with paired serology samples from 2500 Malawian children 0-5 years at baseline and three months to measure age-stratified acquisition of lipopolysaccharide (LPS) O-antigen antibody (IgG) and serum bactericidal activity to the main serovars causing iNTS ( Typhimurium and .

View Article and Find Full Text PDF

Background: Randomised controlled trials of typhoid conjugate vaccines among children in Africa and Asia have shown high short-term efficacy. Data on the durability of protection beyond 2 years are sparse. We present the final analysis of a randomised controlled trial in Malawi, encompassing more than 4 years of follow-up, with the aim of investigating vaccine efficacy over time and by age group.

View Article and Find Full Text PDF

Background: Typhoid fever is a substantial public health problem in Africa, yet there are few clinical trials of typhoid conjugate vaccine (TCV). We assessed immunogenicity and safety of Typbar TCV in Malawi.

Methods: This substudy was nested within a phase 3, double-blind, parallel design, randomised controlled trial of TCV in children from Ndirande Health Centre in Ndirande township, Blantyre, Malawi.

View Article and Find Full Text PDF

Background: Typhoid fever caused by multidrug-resistant H58 Typhi is an increasing public health threat in sub-Saharan Africa.

Methods: We conducted a phase 3, double-blind trial in Blantyre, Malawi, to assess the efficacy of Vi polysaccharide typhoid conjugate vaccine (Vi-TCV). We randomly assigned children who were between 9 months and 12 years of age, in a 1:1 ratio, to receive a single dose of Vi-TCV or meningococcal capsular group A conjugate (MenA) vaccine.

View Article and Find Full Text PDF

Background: To determine the efficacy of a new typhoid conjugate vaccine in an endemic setting in sub-Saharan Africa, the Typhoid Vaccine Acceleration Consortium is conducting a phase-3 randomized controlled trial in Blantyre, Malawi. This article describes community and stakeholder engagement activities before and during the trial, challenges, and lessons learned.

Methods: In October 2017, Malawi-Liverpool Wellcome Trust (MLW) organized a wide range of community engagement activities, including meetings with Ministry of Health and Education officials at the district and facility level, local community leadership, and parent teacher association groups.

View Article and Find Full Text PDF
Article Synopsis
  • Typhoid fever is caused by the Salmonella enterica serovar Typhi (S. Typhi) and primarily affects children, especially those under 15 years of age, with rising concerns for younger children and multidrug-resistant strains globally.
  • * The study tests a new typhoid conjugate vaccine (TCV) in a randomized trial involving 28,000 children aged 9 months to 12 years in Malawi, comparing its efficacy against a meningococcal vaccine.
  • * Results will include monitoring for typhoid illness and evaluating the vaccine's safety and immune response for at least 2 years, aiming to significantly protect children in high-risk areas.*
View Article and Find Full Text PDF