Susanna Dunachie: Vaccines for vulnerable populations

I'm Susanna Dunachie, I run the Tropical Immunology Research Group in Oxford as part of the Centre for Global Health Research. My area of interest is researching vaccines for vulnerable populations. In particular, I've spent many years working in Southeast Asia. I lived in Thailand for some years, and I have collaborators in Vietnam, Indonesia, Bangladesh, India and also in Kenya and Zimbabwe. I'm interested in how to protect people who are more vulnerable to infection. People can be more vulnerable because of older age, because of diabetes, because of immune compromise, and my research has focused on better understanding these people.

We learned a lot from COVID, from studying vaccine responses in COVID. I've worked a lot on melioidosis, but what I'm currently busy with is finding new vaccines for bacteria that cause antimicrobial resistance. In particular, I'm focused on finding vaccines for E. coli and Klebsiella. What our group is trying to do is identify immune responses to key virulence factors, that's danger signals in the bacteria that protect people. What we want to do is study healthy people and how they protect themselves against severe infection from these bacteria and work out how to boost the immune systems of people with more frail immune systems (because of older age, diabetes etc.) so that they can respond to bacteria like healthy people and not get sick.

Those big questions in my field are first of all why do some people get more infections? Why do people with diabetes get more infections? Why does immunity wane as we get older, and older people get worse infections? A key problem is working out how to measure who is protected against infections and who isn't; this is known as correlates of protection. What we want to find is markers in the bloodstream that predict if somebody is protected against disease or not, and it predicts if vaccine works. This is a very big question, it's very important for monitoring vaccines, for working out who's vulnerable and working out how to use resources. We're particularly interested in T cells which are the group of white blood cells important for protection.

Ultimately what we want to do is design new vaccines to reduce death, so we're researching melioidosis, E. coli and Klebsiella. What we want is vaccines that we give to people who are vulnerable, so that they don't die from these infections.  These vaccines are particularly for people living in the world's poorer regions in low- and middle-income countries. We also want to do better at defining who is vulnerable and who isn't, so we do a lot of work on defining in the blood markers of protection.

Our research matters very much because many people die from bacteria around the world. If you look at bacteria that cause antimicrobial resistance, E. coli and Klebsiella are in the top four bacteria associated with deaths from antimicrobial resistance worldwide. Antimicrobial resistance is getting worse, and therefore we need solutions now in order to prevent some infections being untreatable in the future. I also work on melioidosis; this kills an estimated 89,000 people a year. It's very neglected around the world, and it's really important that we have some solutions.

This interview was recorded in July 2024.