This is What the Pandemic COVID-19 Will Add to Epidemiology Textbooks

Truly novel observations included the effectiveness of mass-lockdowns and mass-testing, but also the emergence of groups that doubt the effectiveness of those measures.

Epidemiological science will primarily remember the year 2020 for three major novel observations that cannot be found in existing epidemiology textbooks.

The first significant new insight was the sudden effective implementation of extremely strict lockdown for more than 50 million people in the Chinese city of Wuhan and the Hubei province back at the very beginning of the pandemic. Faced with a new and unknown virus that seemed to threaten the lives of a large number of their citizens, the Chinese authorities did not hesitate about what to do. They quickly and decisively applied a truly dramatic measure, on a scale never before tried, and achieved a notable success. They showed the rest of the world an important fact: that the epidemic of any dangerous new infection can be stopped at an early stage by a strict and massive lockdown in a large geographical area. This temporary measure should buy time for critically important early research, e.g., clarifying the basic features of the pathogen, assessing its mode of transmission, pathogenicity and the speed of spread, developing diagnostic tests, studying the effectiveness of existing drugs, purchasing protective gear and educating the population.

Another significant epidemiological novelty was the experiment of mass testing of the entire adult population of Slovakia, in order to curb a strong second wave of the pandemic without the need for a massive lockdown similar to that which was imposed in Wuhan. Nothing like this has ever been tried before in the history of medicine. A similar measure was resorted to by some Chinese provinces and cities when faced with new local hotspots, as well as the city of Liverpool in the UK.

National lockdowns, i.e. quarantines for the entire populations of individual countries, are very blunt epidemiological instruments for the protection of the population. They should only be resorted to in situations in which more sophisticated measures are not applicable anymore. All nations have been trying to avoid blunt lockdowns ever since the first wave of the pandemic ended. That is why such mass testing is a truly interesting epidemiological innovation, by which Slovakia tried to avoid the need for a national lockdown in response to the intense second wave of the COVID-19 pandemic in Europe. Organising the mass testing of their entire adult population at two points in time allowed them to understand, in real-time, who was infected and who was not, and to separate them so that the infection would no longer have the chance to spread.

That approach turned out to be successful, regardless of the criteria used to evaluate it. The incidence of newly detected cases of infection decreased by 58% within one week in 45 regions that underwent two rounds of mass testing. After further adjusting the observed results to the epidemiological context, the effectiveness of this measure increased to 61%, and compared to the free growth scenario, the decrease was as much as 70%. This means that the mass testing approach in Slovakia has shown very significant effectiveness.

Following the Slovakian experiment, mass population testing could become a new and much more elegant way of dealing with large and intense waves of a pandemic than a general lockdown. Voluntary mass testing could begin to be offered in larger cities around the world where there is a very rapid spread of the virus, as recently shown by the positive example of Liverpool. We’re likely to have more pandemics in the future, so the insights from 2020 may prove to be valuable for some future application.

After this pandemic, yet another chapter will have to be added to the epidemiology textbooks. It relates to something that would have been difficult to imagine in the last century. Namely, in addition to the emergence of groups that present pseudo-scientific arguments to raise public suspicion about the efficacy and safety of vaccines, a whole new group emerged during the COVID-19 pandemic. This new group raises public suspicions about the effectiveness of anti-epidemic measures such as lockdowns, mass testing and various other restrictions. They use unscientific and often very populist arguments, trying to attract the following that was in some way negatively affected by such measures.

Following the COVID-19 pandemic, a whole new branch of epidemiology will need to be specifically developed to study effective approaches that could be resorted to in order to reduce the detrimental impact that such groups had on public health and safety during the COVID-19 pandemic. Such groups were often given quite a lot of media attention, but this is where media and science become incompatible. In science, all evidence eventually converges to a single truth. In media, there has to be a continuous public debate.

This is why many views which the scientific community would consider erroneous were still regularly exposed to the public through different outlets, ranging from social networks to the mainstream media. In most countries, false hypotheses and implausible theories about COVID-19 pandemic gained a considerable following that was entirely disproportional to their credibility and importance. This phenomenon is certainly a 21st-century problem fuelled by the free internet, but the solution is far from clear. It may not be realistic to expect from the media editors to become judges about who should be invited to speak about issues that are so complex that they do not understand them well themselves. Ideally, the general public should become much better educated in critical thinking, so that the large majority of citizens could learn how to recognise and dismiss fake news more readily.


Declaration: Professor Igor Rudan, FRSE, is the President of the International Society of Global Health; co-Editor-in-Chief of the “Journal of Global Health”; Joint Director of the Centre for Global Health and the WHO Collaborating Centre at the University of Edinburgh, UK.

TWITTER: @ProfIgorRudan

FACEBOOK: Professor Igor Rudan



Translation Assistant: Lauren Simmonds

Image credit: Sharon McCutcheon,

Director of the Centre for Global Health and the WHO Collaborating Centre at the University of Edinburgh, UK; Editor-in-Chief, Journal of Global Health