It was 1991 when I was working on a campaign to clean up neighborhood parks in London with a local charity. That's when it clicked for me: we need to do the right science to make the most impact. This seemingly humble moment would go on to guide the rest of my career in public health and my work in immunization sciences, but let me explain.
The calling to public health
I was working as a medical microbiologist on a research project to clone DNA from a dog roundworm, Toxocara canis, a cause of blindness in children. At that time in London, leash rules for dogs in parks were relaxed at best, and they had free-rein in neighborhood parks. Children were playing in areas that were contaminated with dog faeces, putting them at risk of blindness.
My laboratory research project at this time had a strict microbiology focus. It is possible that this information could potentially be used one day to develop a vaccine, but this was far beyond the scope of my project. But what if it didn't have to be? What if instead, we could research how to ensure that children are never exposed to the parasites in the first place?
At this moment, I realized that I wanted my research to translate to tangible, real-world changes that impact health. Basic research is invaluable to the scientific realm, however I was interested in research with immediate impact. I still wanted to do science, but I wanted to do the right science to make the most impact.
With this in mind in 1992 I switched career tracks from microbiology to public health. After completing a master's degree in 1995, I was selected to be the first UK fellow in the European Programme for Intervention Epidemiology Training (EPIET) and moved to the Institute for Hygiene and Epidemiology in Brussels, Belgium. My first foray into immunization sciences was during the EPIET one-week vaccine course that I attended in Helsinki, Finland. The organizers had arranged for the late Dr. Artur Galazka to join us, who was a legend in the global immunization realm. Dr. Galazka was one of the foremost experts in the field of immunization at the World Health Organization, including his work in diphtheria. Diphtheria is an example of how an obsolete pathogen can come back to rear its ugly head. Following the collapse of the Soviet Union, socioeconomic instability, deterioration of public health infrastructure and inadequate vaccine coverage had created the perfect storm for the largest outbreak since the 1960s. A disease of the history books had exploded back into the present.
Finland is one of the leading countries in immunization sciences. Meeting Dr. Galazka and hearing him and other inspirational speakers discuss their work cemented my interest in immunization and its value and impact on a large scale. In my mind, this melded perfectly with the idea to do the right science to make the most impact. Following my field epidemiology training, I returned to the UK to work in the Immunization Department at the Public Health Laboratory Service (later the Health Protection Agency, now Public Health England). At the same time I sustained my connections with Europe through establishing the EPIET Alumni Network (EAN) and serving as its first President, as well as becoming a Scientific Editor for Eurosurveillance, links which I enjoy to this day.
Back to England
Back in London in England, one of my first projects, commissioned by Dr. Philippe Duclos, was a World Health Organization (WHO) project on the global burden of pertussis in 2000. Starting with an approach developed by Dr. Galazka, I developed a simple methodology to assess burden of disease. Despite advances in the field, WHO is still using the same method I developed over a decade and a half ago; sometimes a simple solution is the best solution.
Around this time, there was a major outbreak of pertussis in London. I worked with Dr. Liz Miller, a world renowned immunization expert, on a study of pertussis in pediatric intensive care units and hospital wards. This work provided evidence to support a new pertussis booster program as well as forming my doctorate at Cambridge University. The project exemplified doing the right science to make the right impact
A few years later, a major multi-center study of the burden of Encephalitis evolved out of a project with the Encephalitis Society to promote MMR vaccination for preventing encephalitis. This study created new national and international collaborations, led to a laboratory diagnostic algorithm to improve patient investigation and care, and was one of the most highly cited papers in Lancet Infectious Diseases.
About Dr. Natasha Sarah Crowcroft Dr. Crowcroft is Chief of Applied Immunization Research and Evaluation at Public Health Ontario, and Professor at the University of Toronto. She works at provincial, national and global levels on a range of immunization topics including immunization training, vaccine effectiveness, pertussis and measles and rubella elimination, has contributed to around 200 scientific publications and is an Associate Editor for Eurosurveillance. She was a member of the Canadian National Advisory Committee on Immunization from 2008–2013 and is currently a member of the WHO Strategic Advisory Group of Experts Working Group on Measles and Rubella and the South East Asia Regional Office Measles and Rubella Regional Verification Committee. She studied at undergraduate, masters and doctoral levels at the Universities of Cambridge and London, and trained in clinical medicine and public health in the UK and in field epidemiology in the European Programme for Intervention Epidemiology Training (EPIET).
New challenges in Canada
In 2007, I left England for Canada to begin a new phase of life in the province of Ontario. Ontario has about a quarter of the population of England, but more than 8 times the amount of land mass. I am based in Toronto, Canada's largest city, and one of the most diverse cities in the world. When I arrived, I was pleased to discover that work I had led in the UK on immunization training for health care providers had been adapted by the Public Health Agency of Canada. I served as a member of the National Advisory Committee on Immunization (NACI) from 2008 to 2013. I was a member of a task group to review The National Immunization Strategy that contributed to the establishment of the Canadian Immunization Research Network (CIRN) launched in 2014, in which I remain an active participant.
Canada was one of the few western countries that was significantly affected by the global severe acute respiratory syndrome (SARS) epidemic of 2003. Ontario in particular experienced hundreds of cases, and 25,000 people placed in quarantine. Toronto was the epi-center for the outbreak in Canada with 400 confirmed cases, 25,000 people placed in quarantine and 44 deaths. Though today Ontario has a much stronger provincial public health system, when I first arrived in 2007 I was taken aback. Coming from the UK, I left a well-established public health system that had incredible access to health data, laboratory resources, and other surveillance resources. In Ontario, there was tremendous opportunity for growth. My arrival coincided with efforts already underway to renew the system and my new role was going to be part of this.
In 2008 the province established Public Health Ontario (PHO), a new public health agency. The goal was to strengthen Ontario's capacity to provide scientific and technical advice for the health and public health sectors. This was the brain child of the late Dr. Sheela Basrur, an inspirational leader who I had the honor to meet during the launch of the organization. As a Medical Director, I was tasked to build a new surveillance and epidemiology function for the young agency. There were many challenges in the early days. It takes time to build a new team and a new organization, and we were trying to strengthen the system at the same time as responding to outbreaks including the 2009 H1N1 influenza pandemic.
Despite the challenges, I look back fondly on the early days of PHO. Our collective efforts helped to grow the agency rapidly. We formed our identity and demonstrated the improvements in Ontario public health response system. We successfully conducted a range of applied research during the 2009 influenza pandemic including studies of the sero-epidemiology of pandemic influenza, predictions of how many Ontarians would agree to have the pandemic influenza vaccine, and a validation study of the association between seasonal influenza vaccine and increased risk of pandemic influenza. PHO has undergone transitions, mergers, relocations and reorganizations yet managed throughout to develop and grow applied immunization surveillance, research and evaluation as strengths of the organization. We have forged strong relationships with a multiplicity of public health and research partners. We are a far cry from the early days.
Applied immunization research and evaluation
In 2015, I took on the role as the new Chief of Applied Immunization Research and Evaluation at PHO. PHO identified applied immunization research and evaluation as a new organizational priority. The initiative promotes inter-disciplinary, innovative and policy-relevant research that can maximize the impact on public health practice. Ontario faces challenges that are familiar everywhere, including vaccine hesitancy, inadequate immunization coverage and incomplete data on vaccine safety and effectiveness. PHO is well positioned to support and conduct research and evaluation across the organization and with external partners that can directly address these problems. Through this exciting new work, we are embodying the need to do the right science to make the most impact.
Measles, rubella and CRS elimination
A new dimension to my international work started in 2010 when I joined the Pan-American Health Organization's (PAHO) International Expert Committee (IEC) for Documenting and Verifying Measles, Rubella, and Congenital Rubella Syndrome Elimination in the Americas. The IEC worked closely with a fantastic team at PAHO and country leaders. It has been careful technical work, supported by amazing colleagues and experts. What I didn't expect was for the first major outbreak to threaten measles elimination to happen in Canada in 2011.
As a culmination of a huge effort, PAHO was proud to announce in 2015 that the Americas were the world's first region to eliminate rubella and congenital rubella syndrome. In September 2016, the IEC was able to verify that the Americas had also eliminated measles. Although my work for PAHO was completed in 2016, I continue to support elimination of measles and rubella through membership of the WHO Strategic Advisory Group of Experts (SAGE) Working Group on measles and rubella, and in 2016 I joined the South East Asia Regional Verification Committee. The lessons from the world stage can certainly be applied closer to home, as we recognize the necessity of strong political will in ensuring strong public health systems reach everyone, and the challenges in dealing with parental hesitancy.
Looking toward the future of immunization sciences
In Ontario, we have some of the brightest minds in the world, a good health care system, and supportive communities. We have all the ingredients to be a powerful force for good. Part of the joy working in the field of immunization is its diversity, and the scope is ever-expanding. For example, a novel project with the University of Toronto's Jackman Humanities Institute is on how to capture the public's attention and imagination in telling the story of vaccines through the arts. By working with those outside of our normal scientific and research realms, perhaps we can better help the public understand and trust science. But among all the changes in the field, I remain driven by the same goal; to do the right science to make the most impact.