Student Conversations: From molecules to populations
When COVID-19 locked the world down, Zac Doan found himself glued to news updates, fascinated by how public health decisions were being made in real time.
With a background in biomedical science, he wanted to understand not just the biology of disease but how research findings are translated into action to protect communities.
Zac wasn’t content with being a ‘couch epidemiologist’—his curiosity led him to the Master of Applied Epidemiology (MAE) program at the Australian National University (ANU), where he worked on the topic of communicable diseases in Queensland.
More recently, Zac stepped further down the public health pathway to the World Health Organization’s (WHO) Western Pacific Region Office.
As a Regional Fellow in the office’s Field Epidemiology Fellowship Programme, he spent seven weeks working with the WHO Health Emergency Information and Risk Assessment team in Manila, in the Philippines.
The program has trained more than 200 public health professionals across the Western Pacific region in the past two decades, equipping them with skills to detect outbreaks, assess risks, and support early warning systems.
During his Fellowship, Zac helped assess several emerging health events, including the hantavirus threat aboard the expedition cruise ship MV Hondius.
In this edition of Student Conversations, Zac reflects on the transition from laboratory science to public health, his experience at MAE and WHO, and the lessons he hopes to carry into a career in health emergency response.
You come from a biomedical background. What led you to make the shift into applied epidemiology?
My biomedical background and public health share the same goal, but not the same pace. One is mostly a meticulous exploration in a controlled laboratory; the other is fast, on-the-ground improvised response in the field.
I wanted to cross the divide between slow, steady laboratory science and the fast, on-your-feet response that a crisis demands, and to be part of how scientific findings are used to protect communities.
What was the most valuable lesson you learned during your MAE years?
The MAE's greatest gift was realising the importance of collaborating with stakeholders to solve complex problems. The program pulls together scholars from genuinely different backgrounds. Through placements and collaborative work, I learned that complex problems rarely have clean solutions. You overcome them by bringing the right people into the room.
How did your MAE experience prepare you for the WHO Fellowship?
What the MAE gave me for the Fellowship was the confidence to walk into an unfamiliar environment, engage across professional and cultural lines, and contribute from day one.
What does it mean to be part of a WHO regional health emergency team?
It placed me inside a multi-country defence system, which was very different from the Australia-focused work I did during the MAE.
At the WHO, health security is a shared architecture. A gap in one country’s capacity is a vulnerability for its neighbours and for the whole region. Working there showed me the scale of coordination required to build preparedness across Member States with vastly different resources, geographies, and priorities.
Being part of that system, even briefly, has been one of the most meaningful experiences of my career so far.
What was a typical working day like at WHO?
My typical day revolved around surveilling unusual public health events across the region, drafting epidemiological updates, and delivering technical risk assessments that WHO and Member States rely on.
These included three tropical cyclones, Vaianu, Sinlaku, and Maila, hitting in quick succession, where I had to read the public health implications in real time, alongside ongoing risks from mpox (formerly monkeypox) and measles. The window for useful interpretation was narrow.
What was the most challenging situation you worked on during the Fellowship?
The highest-stakes work involved a hantavirus threat on the vessel MV Hondius—information was fragmented, the timeline was urgent, and there was no precedent for this exact scenario.
I synthesised available information and outlined a plan for risk communication and information acquisition to guide the early response.
It taught me what it feels like to work at the edge of what's known.
One of your Fellowship projects focused on public health emergency preparedness. What were you working on?
I undertook a small project analysing how two parallel disaster and health monitoring frameworks, the Sendai Framework for Disaster Risk Reduction and the IHR State Party Annual Report (SPAR), interact with each other.
Despite overlapping across surveillance and health emergency preparedness, the two systems largely operate in isolation—and this disconnect has direct real-world consequences.
Connecting the two reporting systems would give countries a far more comprehensive picture of their operational readiness: less duplication, a clearer baseline, and better-informed decisions before an outbreak hits.
Looking back, what was your favourite aspect of the Fellowship?
The people.
What about them?
The team involved me in everything they worked on, which gave me endless opportunities to probe and dig deeper.
I asked a lot of questions, and this environment rewarded my curiosity. Every conversation was a valuable lesson in outbreak response, emergency management, risk communication, and regional health systems.
What I valued most was not just the answers, but the chance to observe how health experts think. Watching the logic behind a decision as it forms is a different kind of learning. I could not get enough of it.
How has the Fellowship shaped your thinking about your future career?
The fellowship gave me a clearer sense of the public health landscape. Surveillance, rapid response, scientific research, communication: each plays an indispensable role.
I leave more committed than before to building a broad, adaptable skill set and staying open to opportunities at the intersection of science, public health practice, and emergency response.
What would you advise future students interested in international fellowships like this?
Engage with people from different backgrounds. Valuable lessons can come from watching how others, with entirely different training, approach the same problem.
What would you say to people considering a move into public health in general?
Stay curious and stay open to opportunities that expand your perspective.
I came into the MAE from biomedical science knowing very little about epidemiology or public health systems. My entire reality had been microscopic: organisms and molecules. Scaling from that world to human populations is disorienting, and that disorientation is part of the thrill.