New blood-free tetanus test could help identify global immunity gaps

University of Birmingham experts are developing a non-invasive saliva test that - within 15 minutes - might identify children across the Global South missing immunity to tetanus who may also have missed out on essential vaccines.

Life-saving childhood vaccinations fail to reach over 20 million children worldwide and the COVID-19 pandemic resulted in global coverage of diphtheria-tetanus toxoid-pertussis vaccine hitting a 15-year low, increasing those at risk of serious disease. Despite a general decline in global tetanus, this disease continues to cause unnecessary deaths in some low-middle income countries (LMICs).

Backed by £1.1 million of Medical Research Council funding, researchers are creating a low-cost lateral flow test that enables immunity to be tested easily, quickly, and without taking blood – which is currently the case.

Once the test has undergone laboratory testing, it will be evaluated in Rwanda in partnership with Rwanda Biomedical Center, the Africa Centre of Excellence for Sustainable Cooling and Cold-chain (ACES) and the Center for Family Health Research, based in Kigali. Researchers will assess how well the test works in real-life and discover how acceptable the test is among the local community.

Dr Jennifer Heaney, Research Fellow, University of Birmingham, commented: “Tetanus is a bacterial infection with a high death rate but preventable with vaccination. Eliminating the disease has been achieved in many countries, but in some countries, tetanus is still a public health problem and continues to cause unnecessary deaths every year.

“Our test shows if a person has protection against tetanus within 15 minutes. It can help identify individuals who are not protected and need vaccination. As tetanus vaccination features in all combined immunizations alongside other serious diseases, if an individual is unprotected against tetanus, they are also likely to be missing protection against other serious vaccine-preventable diseases. The test therefore can measure tetanus immunity but could also help identify broader gaps in vaccine provision.”

The test can be used anywhere – whether in outreach, community, clinic, or hospital – and could help to improve access to immunity testing in locations unable to determine protective status and collect sero-epidemiology data. As a non-invasive saliva test, it avoids the need for blood sampling, which can be expensive and is not always desirable, particularly in children.

“To help progress disease elimination goals, it is important to know how many people are protected against disease, but this can be challenging to do directly,” explained Dr Heaney.

“There can be significant differences in immunization coverage not only between but within countries. Having information on immunity at subnational levels can help evaluate how well vaccination plans are working and help inform strategies to address gaps and help ensure protection across the population.”

Dr Christopher Green, healthcare lead for ACES based at The University of Birmingham, commented: “Currently there is a lack of immunity data available to objectively evaluate vaccination systems and prioritize operational planning and deployment. Data from the test could support individual decision making and generate population estimates of immunity coverage.

“Both are important in ensuring we are developing efficient and sustainable vaccination polices. We look forwarded to helping evaluate how well the immunity tool developed works in the field with our Rwandan collaborators at The Centre for Family Health Research.”

The test may later be trialled in other LMICs to measure immunity among different communities and to help support vaccination monitoring and planning.