November 29, 2018

Diagnosing Zika in the field presents specific challenges as other diseases, such as chikungunya and dengue, present in the same areas, can give a false positive on diagnostic tests.

Today, the perfect test to allow a woman, in a remote setting, to do a finger prick test and know in less than an hour, with 100% certainty, that she has Zika, does not exist. The major challenge is, therefore, to produce an accurate test to be used in the field, outside of a sophisticated laboratory infrastructure, that can give a pregnant woman an accurate result rapidly, to allow her to take the next, appropriate steps. Product evaluation and approval are also a challenge, the process is rigorous and can take years to accomplish.

ZikaPLAN Working Group 5, the Platform for Diagnostics Innovation and Evaluation, has two branches. The first is for the development of diagnostics and the second for the evaluation and approval of the diagnostic products, so they can be put into use in the field.

One of the great strengths of the ZikaPLAN network is that it can offer an extensive network of qualified laboratories for multisite evaluation. Sites all over the world are working everyday seeing patients and processing thousands of specimens for all types of disease.

It is this strength that UNICEF recognised in the context of their need for thorough, independent, product evaluation. They chose the ZikaPLAN network to run one-month evaluations of the products they were looking to procure for Zika diagnostics.

In this first round of work for UNICEF, ZikaPLAN laboratories and qualified sites in Senegal and Columbia, used their own specimens to test the products. The multisite nature of the testing has the further advantage of achieving geographical representation for the tests.

Following the initial phase when systems were set-up, protocols were established, and signatures gathered from the authoritative bodies, the first round is now complete. The analysed data and report have been sent to UNICEF and to the ZikaPLAN scientific steering committee. ZikaPLAN has made recommendations and UNICEF will now make final decisions as to whether they will be procuring the products to distribute or not. ZikaPLAN will now be working with UNICEF on their second call.

This rapid progress is remarkable and is the result of dedicated collaboration and team work. In this case, it is clear that, thanks to the structure and organisation offered by the ZikaPLAN network and the coordination by the London School of Hygiene and Tropical Medicine, the results are powerful.

A further mark of progress is the fact that the diagnostic development under ZikaPLAN is being carried out within the countries concerned. For years, products have been developed in the West and brought into low-middle income countries to be sold, but now this is changing. Experts on the ground in countries such as Senegal and Columbia know the need and have the capacity, laboratories and excellent research facilities to develop their own products and collaborate with their European counterparts.

A good example of this today is the work being carried out by the Mérieux Foundation with the Institut Pasteur of Dakar, Senegal on the development and transfer of rapid diagnostic tests. In 2017, two prototype tests were submitted for assessment: an antigen test for the detection of the Zika virus and a serological test for the detection of immunoglobulin M (IgM) and immuno-globulin G (IgG), which are antibodies produced as part of the patient’s immune response against the virus. The first evaluations were carried out in Lyon and at the Institut Pasteur of Dakar.

The prototype of the antigen test successfully detected virus strains and the performance of the serological test was superior to that of both the CE marked, rapid tests currently on the market and also to the ELISA tests used in laboratories. These tests could be used as companion tests before and after immunization campaigns. Over a period of two months, two research scientists and two quality specialists from the Institut Pasteur of Dakar were trained by the Mérieux Foundation in the development of these prototypes as well as in production standards and regulations.

This collaboration, which began within the framework of ZikaPLAN, has inspired the diaTROPiX initiative with the Mérieux Foundation, Institut Pasteur of Dakar and the IRD (Institut pour la recherche et le développement). The purpose of the project is to develop and produce an affordable supply of rapid tests to control neglected tropical diseases in developing countries.

“When busy sites are working together across the world toward the same goal, it means something. It is clear to all that it is so much more powerful to work together.”

Debi Boeras, Ph.D., The Global Health Impact Group and ZikaPLAN Working Group 5.