18 May 2020

A field epidemiologist’s view on COVID-19

UEA graduate Dr Charlotte Christiane Hammer works with the European Centre for Disease Prevention and Control and the World Health Organisation. An experienced field epidemiologist, she’s been helping in the efforts to combat the spread of COVID-19. She explains the vital role field epidemiologist play in tracking and fighting the disease, and how contact tracing is the key to getting out of lockdown.     

people wearing face masks

Epidemiology is the study of determinants of (ill) health among populations. It‘s gained a lot of interest over the last few weeks. In fact, we‘ve seen an epidemic of armchair epidemiologists unfold alongside the COVID-19 pandemic. 

One really important but rarely discussed component is field epidemiology – the application of epidemiological methods in practical situations. As field epidemiologists we conduct outbreak investigations, gather and analyse surveillance data, and conduct operational research. Field epidemiologists come from a variety of backgrounds. They could be a local health officer or an academic working for the WHO.   

In normal times I would work on a number of ongoing projects and on a range of diseases, such as surveillance for Tularaemia, risk factors for Lyme disease or the impact of a change in the law on health care worker vaccination for influenza. Some of us are also usually deployed internationally. Recently I was actually working for the WHO on the still ongoing Ebola outbreak in the Democratic Republic of the Congo and on missed opportunities for vaccination in Zimbabwe. We also regularly teach and train health care workers and students on infectious disease epidemiology and other related topics.  

And then along comes an emergency like COVID-19. For some field epidemiologists this means keeping focused on the other health issues – these don’t simply disappear. For others, it means focusing on a response.  

Your main goal is to control the outbreak and if possible, to stop all transmission, which is much more difficult at a global scale. The practical strategies for achieving this will differ from setting to setting and different circumstances will dictate what action can be taken – just think about what a lockdown, social distancing, and hand hygiene mean in a refugee camp or an informal urban settlement. It is crucial that the local situation, alongside customs and what is acceptable to the population, is taken into consideration. We therefore work with professionals from health care, microbiology, social sciences, law and government to respond holistically. 

Containment measures and outbreak control measures can also be difficult to implement and the main lesson to be learned from previous outbreaks is to engage communities early on. As we’ve seen during the Ebola outbreak in the DRC, there can be considerable resistance from communities if they are not involved early and engaged with respectfully, or if a response is intentionally or unintentionally politicised. 

We have to keep in mind that in Europe we have, for many years, lived in societies that are dominated by liberal freedoms and individualism. In such societies measures for the public good might be particularly difficult to accept because they seem contrary to some of our basic understandings of our rights. Additionally, the very nature of science means that recommendations change with new evidence, but this can be very difficult to communicate and might make people doubt the evidence-based process as a whole. 

At present, I think many people still believe in a silver bullet and that we’ll soon be back to normal. But that is not the case. We are in this for the long haul and we need to keep a balance between keeping everyone safe, keeping the healthcare system from being overwhelmed and keeping as many of our basic rights as possible. At the same time, we need to be very careful not to introduce further discrimination in the response to COVID-19, particularly with regards to the homeless, migrants, and other marginalised populations.   

Adequate contact tracing is the key strategy for countries getting out of lockdown and scaling this up is one of the major tasks for field epidemiologists right now. This means that we try to find all persons that have been in contact with confirmed COVID-19 cases and follow those contacts until they have cleared the incubation period. In fact, you can go so far as to say that the reason for a lockdown, along with flattening the curve so as not to overwhelm the healthcare system, is to buy time to scale up contact tracing and testing.   

In the COVID-19 response so far both traditional methods – enumerating contacts of cases by interview and regularly phone contact – and newer digitally-empowered methods using apps and special databases have been used. This can seem like an enormous task, especially when there are many cases or when each case has large numbers of potential contacts. Contact tracing is one of the most human resource heavy tasks in public health but it’s also a task that people can be trained to do with relative ease.   

And how well can we get ready for a pandemic like COVID-19? Pandemic preparedness means monitoring of global infectious diseases trends, maintaining a functioning healthcare sector and having up-to-date emergency plans. On a more global level – and I mean this both geographically as well as politically – issues such as disease emergence become important. Most diseases with pandemic potential come to us from animals and their spread to humans is heavily influenced by habitat loss, climate change, and other ecological factors that we as humans can directly influence. Preventing disease emergence through conservation is as important as adequate funding for our global public health bodies like the WHO that monitor and prepare for pandemics.