Pandemics: Past, present and future

Just a year after the WHO added "Disease X" to their list of infectious disease threats, we were hit globally with the SARS-CoV-2 virus, COVID.

As Professor of Epidemiology and head of the PandemiX Center at Roskilde University in Denmark, Lone Simonsen worked closely with Danish health authorities investigating and proposing ways to optimize efforts against the pandemic. In Sweden we had Anders Tegnell, whereas the Danes had “Corona Lone”. 

When invited to hold a lecture at the LUSEM Centre for Economic Demography, Lone Simonsen gave insights into the work at PandemiX, highlighting the work with Covid and how they made use of information on earlier pandemics.

“Basically, we took the phenomena of pandemics and put them on an imaginary autopsy table to see what they are all about. From how they emerge to what happens during the pandemic and how it ends,” says Lone Simonsen about her work at the PandemiX Center.

With COVID the Danish expert group tried to find out how pathogens evolved during the pandemic and how human interventions have affected the impact of it. It’s a very differentiated group spanning fields such as epidemiology, economic history, bioinformatics and mathematics just to mention a few areas. 

The Center studies the “Signature Features” of COVID-19 and past pandemics (influenza, cholera, smallpox). In essence that entails the use of mathematical models on historical data of past pandemics.

Among the signature elements of COVID were: 

• The fact that a single virus bearer could infect many without him-/herself showing any symptoms, thus     making it harder to track. 
• That the virus mutated several times and certain strains were more likely to infect people at a higher rate, whereas other strains gave graver symptoms. 
• That unlike the Spanish flu of 1918 it hit the elderly population the hardest. In 1918 the older population had experienced the Russian flu pandemic of 1889 and were to an extent immune to the new one. 

“Also, now that we have better knowledge of pandemic signatures, we can become better at discovering them even with lesser data. This becomes important both in historical studies and when trying to identify a pandemic at an early stage,” says Lone Simonsen.

A group of researchers at the Department of Economic History at LUSEM are involved in a project under the umbrella of NORDEMICS, that is headed by Lone Simonsen. They are specifically looking into tuberculosis, and Doctoral student Liuyan Shi’s thesis will study different measures against tuberculosis and the long term intended and unintended effects of vaccination. Unintended effects may be protection against other diseases, like COVID for instance.  

Thanks to the extent of digitalized data, it was possible to map and analyse past pandemics. In the Nordic countries these types of data, can be traced back 300-400 years. Importantly, the societal context (wars, migration, mitigation strategies, etc) can also be studied to interpret observed patterns and impact.