"When it comes to infectious diseases, we're still vulnerable"

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 2020 EPFL/ A.Herzog

2020 EPFL/ A.Herzog

An EPFL professor of Microbiology, Melanie Blokesch reminds us why we need to take infectious diseases more seriously - and be better prepared for future outbreaks.

What does this COVID-19 crises teach us about pandemics’ An EPFL professor, Melanie Blokesch heads the Laboratory of Molecular Microbiology. Blokesch and her team study the environmental lifestyle of pathogenic bacteria and their evolvability, focusing primarily on Vibrio cholerae, the bacterium that causes cholera. In this interview, she reflects on what the COVID-19 crisis can teach us about pandemics and reminds us why we need to take infectious diseases more seriously - and be better prepared for future outbreaks.

  • What has surprised you most about this crisis?


We haven’t seen a sudden respiratory disease pandemic like this for a long time. The last comparable outbreak was the Spanish flu pandemic of 1918, which killed almost 50 million people worldwide. It’s always revealing when I show my students how life expectancy curves changed dramatically in 1918. And although experts anticipated a new pandemic to hit at some point, most countries weren’t ready for it. What I find most surprising is how some countries have taken sharp, decisive action whereas others seem reluctant to adopt strong intervention strategies. It’s also interesting to observe how individuals have reacted. Some people are determined to stay at home while others are still venturing outside with little concern about whether they’ll get infected or infect others. These differences will, of course, strongly influence the course of the pandemic going forward.

  • Can we accurately predict how a pandemic like this will evolve?


Yes, to a certain extent. Epidemiologists have a range of tools they can use to make predictions and guide intervention strategies. For instance, they can analyze people’s movements using gravity models or by tracking cell phone data anonymously. Once you feed the data into the models and estimate other parameters such as contagiousness and length of infection, you can predict how the disease will spread from person to person or, in the case of cholera, from person to water to person. Epidemiological models always have some degree of inaccuracy, especially for a disease like COVID-19, where our understanding of transmission and infectivity is still patchy. But they can still provide useful estimates, such as telling us whether infection numbers will continue rising, stabilize or decline, or suggesting where outbreaks might emerge and spread. Plus, here in Switzerland, we have the advantage - if I dare say so - of learning from how the virus has spread in Italy.

  • When will it be safe to venture outside again?


The answer really depends on how we all act, as individuals. First, we have to get the number of cases down. Then we’ll need to start going out again, in a slow and controlled way. Ramping up our testing facilities is an absolute priority, so we can quickly identify new cases, and so we can trace and isolate contacts. We’ll need to keep the outbreak in check until we have treatment options available, especially for the most severe cases. Clinical trials have already begun on a number of potential therapeutics. Ultimately, the hope is that we’ll have a vaccine. But the hard truth is that it takes time to develop a vaccine and test it to make sure it’s safe.

  • COVID-19 is understandably at the forefront of everyone’s minds right now, but are there any other ongoing global pandemics?


COVID-19 isn’t the only pandemic sweeping the world as we speak, but we don’t necessarily hear much about the other ones in Europe. For instance, the seventh cholera pandemic began in the 1960s and is still with us now. Every year, the cholera bacterium infects around 5 million people globally and the disease claims around 100,000 lives. Cholera gets limited press in the developed world because it doesn’t affect people directly. Personally, I think it deserves a lot more attention. That’s one of the reasons why my group is studying the evolution of this pathogen, and its transmission from water to humans.

  • What are you learning from this new coronavirus outbreak, as an infection biologist?


If the COVID-19 pandemic teaches us anything, it’s that when it comes to infectious diseases, we’re still vulnerable. We tend to focus on noncommunicable diseases like cancer, neurodegenerative diseases and heart failure. But we show only limited concern for infectious diseases because, in recent decades, the developed world has seen remarkable advances in sanitation, extensive vaccination strategies and efficient bacterial treatment through antibiotics - although the increasing prevalence of antibiotic-resistant bacteria poses another threat in the coming years. From a more general standpoint, this outbreak teaches us a lot about human migration, urbanization and deforestation, and about how these factors contribute to the transmission of emerging pathogens from natural habitats and wild animals to humans. This is clearly not the last time this type of thing will happen. We need to be better prepared next time around.