Prof. Andrea Crisanti: “Active surveillance is crucial in containing the epidemic”

Interview on corona virus and what is the best approach to fight epidemic with Andrea Crisanti, professor of Microbiology and Clinical Microbiology and director of the Department of Molecular Medicine at the University of Padua.


From your experience in Italy what should have been the best approach to fight epidemic?

ESMH Scientist Andrea CrisantiI have been repeating since the beginning of the epidemic that until a vaccine is uncovered, the only way to stop the spread is to identify all carriers of the virus including healthy ones. Epidemics must be fought on three levels: with hospitalisation, with containment measures limiting social contacts and with active surveillance.


What does ‘active surveillance’ mean in practice?

Asymptomatic people can transmit the virus, therefore one of the challenges is finding asymptomatic people as well as curing symptomatic ones. Active surveillance on the territory means that if a person calls because he is sick, health personnel goes there, tests the person, but also family members, friends and the neighbourhood, because it is around the symptomatic person that there are healthy carriers and other infected people. We must move in concentric rays around the symptomatic subject.


This is what the experience of the village of Vo’ teaches, right?

Yes. Vo’, in the region of Veneto, is the village that had – on February 23- the first confirmed COVID-19 related death in Italy. Health authorities decided to test all Vo’ residents, around 3300 people, for COVID-19. We found that nearly 3% were infected and that the majority of those who tested positive showed no symptoms. After quarantine, another round of mass testing in Vo was carried out and the rate of COVID-19 infection dropped from nearly 3% to 0.4%. 

I acknowledge that mass testing would be harder to carry out in large cities, but I believes that Italy could have been more proactive in containing the outbreak. As soon as we made data available that the infection rate in Vo’ was 3%, the alarm bell should have rung to health authorities, carrying out extensive testing.


Active surveillance has the limitation that a subject can become infected at a later time…

This is true, however if we map the surroundings of a symptomatic person, we can identify all the other people who are positive and put them all in quarantine, decreasing the probability that they transmit to other people. It is obvious that these people have to be tested again after few days.


In South Korea – where active surveillance has been implemented – there are mechanisms of enforcement of social adhesion that Italy and Europe do not have. Furthermore, there are practical aspects to consider, such as the lack of tests and the ability to process them …

I do not agree. Active surveillance has been carried out over many years with success to reduce the spread of pathogens in developing countries. It requires preparedness and skills that were not there at the beginning of the coronavirus epidemic.


Do you agree with those who argue that case finding and contact tracing are strategies that require large organization and advanced technologies and cannot be put into practice during the pandemic, but only in the initial phases or in the phases following the first peak to avoid a second peak?

Active surveillance is most effective at the beginning and when the epidemic shows sign of decreased transmission because it requires a lot of effort and presence on the field. However, when effectively combined with social distance, it has the power to block the transmission very effectively, as shown in Vo’.


The epidemic has different time-lapses in different European Member States: what implications does this have in the containment of the epidemic?

Obviously, this offers the possibility to learn from the experience of others, though in the very near future a common strategy and approach would be of paramount importance particularly in agreeing the metrics to lift the measure of movement bans and social distancing.


Urbanization and deforestation, are these factors that facilitate the onset of new epidemics?

Preventing epidemics is crucial. For example, we have not taken lessons from the experiences of SARS and MERS to adequately study the origin of these epidemics. Repeated new infections come from China, however Africa is also a potential reservoir of new viruses. Many derive from bats, poultry and pigs, but there are still several other animal species that can give rise to new viral strains.

In light of the new epidemics, we have to better understand what is happening with deforestation and extensive urbanization, mainly in Brazil, Africa and China. Deforestation basically means that the human being comes into contact with a new microbiological world of which little is known. But not only deforestation, also intensive farming can be a source of new epidemics. More research needs to be done to study the jump from species, from animals to humans. The latest epidemics – SARS, MERS, Zika, etc. – have been very close over time: I believe it is important, once this emergency is over, to invest in research more deeply and continuously.


Is there a need to rethink our public health systems after the crisis?

Indeed. Although health is determined by a large number of factors throughout the life course, effective health systems are one of the most important contributors to population health. WHO defines the health system broadly, as “all the activities whose primary purpose is to promote, restore or maintain health” It should be noted that this definition unambiguously embraces most public health and health promotion services. After the crisis our health system should be rethought – more than ever – not as costs but as investments.


You are familiar with the European research system: can the epidemic be an opportunity to complete the European Research Area?

For roughly two decades, Europe’s politicians have talked about the need to make it easier for scientists to work with their colleagues across borders, reducing fragmentation and overlapping, in other words to implement the European Research Area. Unfortunately, despite the talk, the situation has not advanced much. Research mostly remains the territory of individual Member States, with distinct programs and rules. I really hope that the situation can change rapidly: having a common European area of research would prove crucial in a brutal crisis like the present one, for a faster development of a vaccine and for a faster testing and new effective drugs against COVID-19.


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