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Monitor population immunity against vaccine preventable diseases

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Monitoring immunisation levels in the population via microarrays

Despite recent efforts to improve vaccination of children in resource-poor countries, optimal levels of immunisation are not always reached. Indicating administrative records may not be adequate for estimation of the level of protection in a population highlights the need for alternative surveillance approaches.

Health

Poor management of vaccination resources available and challenges to the execution and the reporting of immunisation plans often lead to unsatisfactory protection levels. This is still the case in some resource-poor countries. Vaccine coverage data have been criticised lately as they rely on administrative records rather than on real performance indicators to monitor the progress of vaccination programmes.

A microarray system for quantifying antibody levels

With the support of the Marie Skłodowska-Curie programme, the Vaccinesurvey project addressed this issue through an innovative solution capable of quantifying antibody levels against the major vaccine components. “The Vaccinesurvey tool overcomes both operational and performance limitations of current immunoassays such as ELISAs, and is particularly suitable for resource-poor countries,″ explains project coordinator Prof. Andrea Crisanti. Classic immunoassays are labour-intensive and can process only a few tests simultaneously, making them unsuitable for routine surveys against a great number of different microbial antigens. The multiplex assay is based on microarray technology with indirect fluorescence detection capable of quantifying serum antibodies against 11 different vaccines including tetanus, diphtheria, hepatitis B, rubella and measles. To evaluate the performance of the Vaccinesurvey tool, partners analysed over 250 human serum samples collected in the field, and evaluated the reactivity data against existing immunisation records. Results showed a correlation between experimental data and record-based coverage information, and the majority of individuals achieved full protection levels for the investigated diseases. This clearly shows the potential of the Vaccinesurvey tool in facilitating the analysis of cross-coverage monitoring and the immunisation status of a target population after a vaccination campaign.

Advantages of the Vaccinesurvey tool

The proposed technology offers unprecedented power to monitor the progress of different vaccination programmes through the rapid analysis of blood samples against different vaccine antigens. This solution has the potential to be used as a reliable and accurate diagnostic tool and could serve as indicator of vaccination performance. It also offers a competitive advantage in terms of time, materials and costs particularly for field settings. The next step is to generate a low-cost portable microarray solution for point of care testing such as doctors’ clinics and small district hospitals. Coupling the tool with a mobile phone software application will help read the results promptly. Project partners are currently exploring funding opportunities to further develop the tool and incorporate additional features that will support the capacity building potential of this technology in resource-poor countries. Crisanti emphasises: “Besides the technical results, the most important achievement is the transfer of knowledge and skills between researchers involved in the scientific activities.″ The training and learning through staff secondments between academic institutions and industry not only strengthened collaborations but is expected to maximise the capacity and resources of future immunisation monitoring. Overall, future implementation of this assay system will strengthen the existing surveillance infrastructure of vaccine preventable diseases, offering objective quality control procedures. Additionally, it could help identify regions at risk of disease outbreaks or in need of additional resources, and support strategic plans towards a better use of government and donor-supported funds.

Keywords

Vaccinesurvey, vaccination, immunisation, microarray, serum, monitoring, antibody levels

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3 December 2021