Interview with Dr Mehreen Datoo

A massive milestone in the fight against malaria was reached in 2024 when a new vaccine (R21/Matrix-M™) was deployed, following World Health Organisation recommendation. The vaccine was developed at the University of Oxford in partnership with communities across Africa, and produced at scale by the Serum Institute of India. It was the subject of a major documentary, The Battle to Beat Malaria, featured on the BBC.

Dr Mehreen Datoo is a central member of the Oxford team and was named on the 2024 TIME100 Next list of 100 emerging leaders. She is an Associate Fellow at Green Templeton and a Clinical Lecturer in Infectious Diseases. Observatory sat down with Mehreen to ask about her life and career to date, the vaccine development, and her roles in the college community.

Could you start by telling us a little about yourself?

I’m not one of those people who grew up wanting to be a doctor. In fact, I always wanted to be a teacher. I loved science – biology and chemistry were my favourite subjects at school – and when I was 16 or 17 my friends and I got the opportunity to do a short ’Insight into Medicine’ course at Nottingham University. I thought it would be a couple of days away, a bit of fun, but we did some cool things, and when I came home I told my parents I wanted to apply for Medicine.

My parents were very surprised, and asked me a lot of questions. They reminded me how long medical training can be, but ultimately they were supportive. Given my ethnicity, there can be a stereotype that everyone is going to be a doctor or a professional, which is not true at all. There are no medics in my family, but my parents helped me find people to ask more about the career. I ended up securing a place at King’s College London to study Medicine.

You mentioned your ethnicity. How would you characterise it?

It’s a complicated answer. I’m British born and bred, but my family have raised me with the faith, values and culture of their backgrounds too. My parents were born and brought up in Tanzania before moving to the UK. They studied and worked in the UK, deciding to settle here in the 1970s. My sister and I are first-generation British.

How did you get into tropical medicine?

When I was in medical school there was an option to do a BSc in a year, sandwiched into your medical degree. At that time, there was a BSc in International Health and Policy in Leeds.

It is fair to say that I hadn’t appreciated how much additional debt I was taking on but living in Leeds was a lot cheaper than London, and the major attraction for the course offered by the University of Leeds was the opportunity to do your research project abroad.

So I moved to Leeds for the year, and I did my research project in Uganda. When I was on a short holiday to see the gorillas I got malaria. (The gorillas were spectacular, by the way!) Luckily, after a couple of weeks in hospital, I was able to return home and I was okay after spending a lot of that summer recuperating in my parents’ garden.

Because of that experience and because I had travelled a lot with my parents, infectious diseases interested me. So, after completing my second foundation year as a doctor, I did a short diploma at the London School of Hygiene & Tropical Medicine.

You then went to work overseas?

Indeed. As an early-career doctor I went to do medical outreach work in some rural clinics in Zambia with an NGO called On Africa. We had a base in Livingstone, but Monday to Thursday we would go to different districts and work in community-run clinics. We would return to Livingstone each week on a Friday, spend some time recuperating, and then on Sunday, packed up meds and restocked our vehicle for the next week’s district. It was demanding but rewarding: I saw really sick people whocouldn’t access healthcare in hospitals.

I vividly remember two children who were very ill with malaria. We thought that they were going to die, but with malaria treatment and good nutrition, they got better. The mother brought the children back a few weeks later; I didn’t even recognise them because they were so well. Early diagnostics, appropriate treatment and healthcare are key and sadly many people around the world still don’t have access to the basics. That experience further reinforced the sort of career I wanted to have.

After that you moved to Oxford?

Yes. I applied for my further medical training at Oxford University Hospitals, though I spent my first year on rotation in Slough, west of London. It was a bit of a culture shock coming back to the NHS – for a variety of reasons, including the resourcing constraints and on occasion because of the way junior doctors are treated. I struggled with the way in which access to healthcare was taken for granted, and interventions ignored.

However, I realised that if I wanted to make a bigger difference, I needed to obtain more experience and understand some of the processes better. I knew that I had to learn how to be a good doctor and then become a specialist in infectious diseases.

And then you started a research project?

Professor Adrian Hill advertised for a research fellow and I knew it was to work in malaria vaccines. I saw it as a great opportunity to understand a vaccine candidate that was being transitioned from the lab to the clinic. I hadn’t a clue what it involved when I started working for him, but Adrian and his team have taught me how to do a clinical trial from start to finish. The Jenner Institute has preclinical, laboratory and clinical facilities which are key to translating vaccines to reality, and some excellent people in various teams.

The clinical trial processes are detailed for a reason: you are about to test for a real-life disease and a potentially real-life cure. I learned how to design and draft a compliant protocol according to Good Clinical Practice for a clinical trial; I learned about the ethics and regulatory requirements and then I learned how to implement and run a clinical trial. For me, the real joy in the entire process was looking after the participants, who had bravely come forward to test our vaccine candidate – and for me, as a clinical doctor, this was also one of the easier parts of the job (well, most of the time).

Some of the best parts of my job are the ‘malaria challenges’. First, you give participants a vaccine designed to protect against malaria; second, you give them malaria deliberately through five infectious mosquito bites; and third, you monitor and look after them closely, because you have given them a potentially fatal disease. The challenges are excellent: it’s a huge responsibility but also amazing on a human level.

You get to know your participants really well because you spend about six months getting to know them; and you see or speak to them every day for three weeks, sometimes twice a day. This is because you counsel them, give them vaccinations, do the malaria challenge and follow up with them afterwards. The relationship with your participants is incredible. If you are fortunate enough, you can sometimes see exciting results too.

Did this form the basis of your DPhil?

It culminated with the R21 vaccine. After giving these vaccines and doing a malaria challenge in England, we first took our vaccine to Kilifi in Kenya, to test if it was safe and induced immune responses in our target population of African children. And following encouraging results, we did the same in northern Burkina Faso, verifying that it actually protected against malaria. It was those stages of the trial that I worked on for my thesis.

It was the first time a malaria vaccine had shown vaccine efficacy of over 75%, which was the WHO target at that time. It was super exciting when the data was presented at an international conference, but we didn’t know if anyone believed it. When it was published in The Lancet, it was in writing for all to see.

Then what?

The big problem with vaccines is that it’s not only about making a vaccine and testing it in phase 1, phase 2 and phase 3 trials to check if it works. We also need to be able to manufacture a vaccine at large scale and at an affordable price to reach those who need it most. And of course, through education, encourage people to take the vaccine (or bring their children for the vaccine).

We knew we could never manufacture millions of doses at the University of Oxford and to transfer the technology to the Serum Institute of India for mass manufacture would require complex negotiations. We also realised that you can’t necessarily use the same manufacturing process, and so we had to redo the initial phase 1 and malaria challenge trials.

After my DPhil, and because of these exciting results, I chose to stay in Professor Hill’s group to continue the clinical development of the R21 vaccine. Over the past few years, the work has really ramped up in terms of designing, writing and executing the phase 3 trial protocol, engaging the collaborators in Africa, and leading from the clinical side with partners in the target communities. At the same time, we have been taking scientific advice from various stakeholders and international regulators, as well as  continuously submitting data to the WHO for assessment to enable a policy recommendation and vaccine prequalification.

It was clearly a collaborative, multinational effort

It is critical to remember that although the vaccine was developed in Oxford, it was tested in Africa because that’s where the target population is. None of this success would have happened without the great teams that we have working tirelessly in Africa – and also the participants and their caregivers.

It’s the people who make the clinical trial: the participants and their caregivers have to want to be involved in the trial and do whatever is needed – attend their appointments, consent to vaccinations and the follow-up. And it’s the research study teams that engage them and look after them on a daily basis.

You became a regular in the media?

I never anticipated that it would be part of my career. When I went to medical school, I was going to be a doctor. When I decided I wanted to do research, I was going to be a researcher and a doctor. I never thought that I would have any involvement with the media, but I have come to understand that it is an important communication tool. For example, for malaria, the media offers the opportunity to raise awareness of a deadly disease that is often ‘out of sight and out of mind’, having been largely eradicated in the West.

I’ve also done some research with Ebola and COVID vaccines. Observing the difference in funding between all these diseases has been surprising, but I think you can rationalize it by understanding the populations it affects.

So I hope that by engaging in the media, I’m raising awareness of the diseases and maybe of the funding issues, because there are many diseases that are still underfunded and require a lot of research. And I also hope that I am inspiring others to raise awareness; maybe to work on fighting the less well known diseases or to assist with funding.

You’ve spoken about being a woman of colour at the forefront of research

This is a tricky topic; and there are plenty of strong opinions out there. I can only speak for my own part, my own lived experience, and I have found it difficult to be a person of colour in medicine and science. This is a demanding career to start with, and it takes a lot of time and energy to break down barriers in the field, and too often it’s a burden that minority groups have to carry.

I try to have a voice now, and I have a supportive family who have backed me through any challenges. My personal wish is that if you are reading this, you might feel confident to rise to the challenge of speaking up, to be an ally or a champion; but that you might also listen and think about the voices in the room that might be struggling, or at a disadvantage, and create a safe space for them.

How did you get involved with Green Templeton?

When I moved to Oxford, I didn’t know anybody, and college gave me a community. I first got involved as a Teaching Associate. That’s how I met colleagues and students, and not only in my field. College was also my family, because it was the only place I could come when I didn’t want to be at home. And it was really nice to be involved in all the medical teaching.

The Senior Doll Fellow at the time, Laurence Leaver, facilitated that. He made me feel part of his family, who looked after medical students. I was really proud to be a part of a college and part of the medical school teaching.

Following this, I was recommended to be an Associate Fellow. My role has changed a little; I do less of the clinical bedside teaching now mainly because of my research commitments, but I really enjoy being a college advisor, mentoring master’s and DPhil students, as well as clinical medical students, and providing more pastoral care to them.

Any concluding thoughts?

I’d just say the future is bright. I don’t always know what I’m going to be doing or where I’m going to be doing it, but I do know that I want to be doing something where I can try to help people, whether clinically or through my research. And I hope to inspire other people to make a difference too.