Request for Expression of Interest (EOI): Development, Manufacturing, and Distribution of Rapid Diagnostic Tests (RDTs) and Enzyme Immunoassays (EIAs) for Acute Typhoid Fever Surveillance
Typhoid fever (TF) is a severe systemic illness associated with abdominal pain, fever and occasionally can be life-threatening. TF also referred to as, typhoid, is caused by the Gram-negative Salmonella enterica serovar Typhi (Salmonella Typhi; S. Typhi). Individuals acquire S. Typhi after the consumption of contaminated drinking water or food with faeces of people who have typhoid or from people who are chronic carriers of S. Typhi. Annually, 9 million typhoid cases and up to 110 000 deaths are reported worldwide, with children at the highest risk of contracting typhoid specifically, children aged 5-9 years are the most affected group. The typhoid incubation period ranges between 7 and 30 days, after which patients can present with sustained fever, malaise, diarrhoea, constipation, splenomegaly and sometimes rose-coloured spots on the torso. Without hospitalization and appropriate antibiotic treatment, some patients’ typhoidal disease can progress to manifest severe complications, including intestinal perforation, gastrointestinal haemorrhage, hepatitis, myocarditis, shock, pneumonia, anaemia, and even encephalopathy. Paratyphoid fever, which is caused by Salmonella enterica serovar Paratyphi A, B and C presents as clinically indistinguishable from typhoid. However, patients infected with S. Typhi have more serious complications if untreated. The clinical syndrome of patients infected with either S. Typhi or S. Paratyphi A will be referred to as enteric fever.
Typhoid has contributed to significant morbidity and mortality in many resource-limited countries in South America, Africa, and South Asia, because of the limited potable water supplies and suboptimal sanitation barriers. To combat this human healthcare challenge, on 3 January 2018, the WHO announced the prequalification of a typhoid-conjugated vaccine (TCV) for children older than 6 months and in adults up to 45 years in typhoid-endemic countries. The decision came after the endorsement of the WHO Strategic Advisory Group of Experts (SAGE) on immunizations. WHO recommends programmatic use of typhoid vaccines, though WHO notes that TCVs are the preferred products.
TCV utilization is recommended for typhoid control in countries with high typhoid incidence or high prevalence of antimicrobial-resistant S. Typhi. In addition, to understand the typhoid burden, the WHO recommends that countries conduct typhoid surveillance with a minimal surveillance standard of passive or active case-based laboratory-supported, facility-based sentinel surveillance of clinically suspected typhoid cases. Laboratory confirmation of S. Typhi is critical because clinical diagnosis is nonspecific; also, prevention of typhoid and response to a typhoid outbreak require specific measures.
One of the major hurdles of introducing TCV is understanding the burden of S. Typhi in endemic regions. S. Typhi laboratory diagnostic challenges, particularly, the unavailability of reliable diagnostic assays may impact the implementing TCV in endemic regions due to the lack of typhoid surveillance diagnostic tools.
New typhoid diagnostic innovations are needed for individual patient care decisions as well as for surveillance to guide vaccine and other public health measures. Improved typhoid diagnostics would strengthen surveillance by providing reliable incidence data. Comprehensive mapping of disease burden enables health authorities to identify hotspots suitable for typhoid conjugate vaccine (TCV) introduction. The current typhoid diagnostic challenges emphasize the need for new and innovative S. Typhi RDTs and EIAs that will help in the surveillance of acute typhoid cases.
The first step towards accelerating the development of surveillance tests for typhoid is to develop Target Product Profile (TPP). TPPs are strategic planning tools for guiding the development of new tests and other health care products and serve to inform public health programme requirements, thereby shaping future market offerings. This document describes two typhoid TPPs:
1. A Rapid Diagnostic Test (RDT) TPP, intended to enable decentralized typhoid surveillance testing, away from referral laboratories in LMIC settings.
2. An Enzyme Immunoassay (EIA) TPP to assist in evaluating EIA tests as alternative surveillance tools enabling the confirmation of acute typhoid in LMIC settings if an RDT assay cannot be developed.
This call is intended to Request Expression of Interest (EOI) for development, manufacturing, and distribution of a rapid diagnostic test (RDT) and Enzyme immuoassays (EIA) to be used for acute typhoid fever surveillance.
This call does not have a deadline for submitting their EOI’s. The manufacturers are requested to fill the attached expression of interest documents, whether an RDT or EIA assays and email it back to Dr. Mick Mulders at [email protected].