Gabriel Leung is perhaps the most authoritative voice to speak about the coronavirus COVID-19 in Asia. Or one of the top experts on how to combat it. He is the one who questions the projections of the Chinese regime and those who do not believe that everything will end by the end of April in that great country. Epidemiologist of infectious diseases and dean of medicine at the University of Hong Kong, this renowned doctor alerts the world since January -almost alone- about the dangers of the outbreak born in Wuhan, China, and it spread to the world in the form of pandemic in just three months.

In a column published this Monday in The New York Times, Leung He explained how it will be the way to get out of the quarantines and the mandatory isolations dictated by governments around the world and that this situation cannot last forever. Prolonged, he warns, will cause “tremendous damage to economies and will compromise goodwill and emotional health” of people.

A formal framework, with an explicit science-based rationale, is needed to determine when and how and based on what factors to relax the constraints, and how to reapply some or all of them should another epidemic wave strike again.”, Recommends the Honduran scientist. “Containment has failed everywhere. In some places -Wuhan in February; Northern Italy in March-, the epidemic spread so quickly that the relevant authorities had to focus mainly on mitigating its effects, on damage control. Elsewhere, the crackdown has worked so far: Hong Kong, Singapore, and Taiwan have not experienced sustained local epidemics. Not yet, at least

However the epidemiologist knows that these mandatory confinements closing almost all activity will generate great disruption in the economies, causing damage that no one knows how far they will go. Above all, this worries the powers of Europe and at U.S, summarized. Leung also knows that, logically, “the first goal should be to protect lives and that means avoiding the collapse of the healthcare system

For this to happen, he described hospitals “as the last line of defense”In the battle against coronavirus. “When your ability to handle emergencies is overwhelmed, such as in Bergamo, northern Italy, or areas of Spain, there is little point in theorizing about what I’m about to do: all you can do is roll up your sleeves, connect to intravenously drips and ventilators, and try to save as many lives as possible with any available means

But past that point (or, preferably, sooner), the ultimate goal should be to reduce the epidemic at a slow pace to gain time for the world’s population to acquire immunity to COVID-19 in one form or another. The pandemic can only prevent it from re-emerging when at least half of the world’s population has become immune to the new virus. And that can happen in one of two ways: after enough people have become infected and have recovered or been inoculated with a vaccine“, summarized Leung.

The Honduran scientist explained each of these two options more clearly, also telling how they should be developed: “Allowing the first option to occur, without mitigation, would be a humanitarian catastrophe: it would mean many deaths, mainly among the elderly and the poor with limited access to medical care. The second option, developing a safe and effective vaccine and making it enough for everyone, is a goal in at least a year, perhaps two years. Mass insulation and spacing measurements can’t be kept that long

Leung He explained that during the remainder of 2020 and perhaps something else, it is likely that populations around the world -without the previous steps- they will see different forms of quarantine turn on and off to avoid second waves of outbreaks and infections. “We all need to prepare for various ‘remove and lift’ cycle policies during which restrictions are applied and relaxed, applied again and relaxed again, so that they can keep the pandemic under control but at an acceptable economic and social cost“Explained the academic.

The best way to do this will vary by country, depending on its means, its tolerance of disruption, and the collective will of its people. In all cases, however, the challenge is essentially a tug-of-war of three ways between fighting disease, protecting the economy, and keeping society in balance.“He said.

According to each country, he said Leung, different models of “may be appliedsuppression and lifting”Of the restrictions. “To get started, one needs solid data. Policy should not be determined based on the daily count of reported cases because they are unreliable. Instead, what is needed is the effective real-time replication number of the coronavirus or its actual ability to spread at any given time.inado. And one needs to understand that number correctly, in context. The rate at which a virus is transmitted, known as R-naught (R0), or basic reproductive number, refers to the average number of people to whom an infected person transmits the virus in a population without pre-existing immunity. The R0 can vary from place to place due to the age structure of the population and the frequency with which people come into contact with each other

The ‘effective’ version of that number, the Rt, or the reproduction number at time ‘t’, is the actual transmission rate of the virus at any given time. It varies according to the measures to control the epidemic (quarantine and isolation protocols, travel restrictions, school closings, physical distancing, use of face masks) that have been implemented. The cases reported daily do not convey the true state of the spread of the virus. On the one hand, there is so much heterogeneity in test ability per capita from countries around the world that it would be crazy to try to draw a broad conclusion on the transmissibility of the virus from all that disparate data. On the other hand, reported case numbers delay actual infections by at least 10 to 14 days“he explained.

Leung It also made clear that “the incubation period for COVID-19 is approximately six days” and that in certain nations “some people never get tested, and those who probably don’t until they have had symptoms for a few days.” That is why the daily numbers of infections are not parameters of anything, in his opinion. “However, it is possible to approach the daily count of reported cases to the Rt in real time thanks to statistical adjustments and digital analysis

But Leung goes further. He believes that it is vitally important to know the movements of people and to get the information given by big data to know if social distancing policies are resulting in the fight against coronavirus. “With a little ingenuity, existing digital tools can quickly become epidemic monitoring tools, and without intruding into people’s lives. Those who are generally concerned with invasions of privacy (and rightly so) would not need it in this case: the idea is to study only aggregated and therefore anonymous numbers, to look at big data, not personal information

Then, having determined what the Rt actually is, decision-makers could fine-tune their interventions to keep that number at a level acceptable to themselves and their constituents. An Rt of 1 means that the epidemic remains stable: for each infected person, another becomes infected, and when the first one recovers or dies, the second one replaces it; The size of the total group of infected people remains the same. At a rate less than 1, the epidemic will fade away. Above 1, it will grow, perhaps exponentially“Warns the professor of the University of Hong Kong.

For Leung Each city or government must specify in what percentage of the Rt its infected population is moving. “Each community must determine the effective reproductive number in real time that it can accept given its own circumstances, particularly the stage of the epidemic in which it finds itself. Still, for all communities, that determination essentially requires doing the same thing: calculating the number of new daily infections your health system can handle without imploding.

The academic puts it with clear numbers and a clarifying example: “Imagine a city that has 1,000 beds in intensive care units. You cannot have more than 1,000 people on a respirator at any one time. If the average length of a patient’s stay at the I.C.U. is 14 days, this city cannot provide intensive care to more than 71 new patients per day (1,000 / 14 = 71.42). Assuming that approximately 5 percent of all newly infected cases are so severe that they require intensive care, the city cannot afford to have more than a total of approximately 1,420 new infections per day (71 x 20 = 1,420). This is the actual number of infections, only a fraction of which are reflected in the officially reported count. The authorities, having established the number of new infections that the city’s emergency health centers can support, can determine what Rt they should target and adjust their interventions to achieve it.

Then, once it is clear what the health system can support, one must ask what the economy can accept and, separately, what the people can accept. Even if the healthcare system can tolerate nearly 1,420 new infections a day, would Wall Street, the financial markets, and most importantly, the real economy be scared? Or would they react as they do during a bad flu season? And how long can the population accept the restrictions required to maintain that level of infections? Will people stop complying? Are your mental and emotional well-being at risk?“These are questions that, according to the epidemic expert, governments should ask themselves.

There is no right or wrong answer on how best to respond to a threat as large and complex as this pandemic. One can imagine a variety of individual points of view: “I prefer to protect the economy and risk the epidemic”; “I prefer not to risk it and allow the economy to skyrocket, in part because I am sure it will recover in a year.” ‘I’m already going crazy after a week of confinement; I can’t see myself hanging on to this for three months. ” This rank is the reason why the general public, especially in Western democracies, should have the opportunity to shape this discussion. And yet, despite the fact that different communities will strike a different balance between these interests, the “suppress and lift” strategy is generalizable to all.“, summarized.

By last, Leung concluded: “After achieving a sustained decrease in Rt and reducing the number of new cases daily to an acceptable baseline thanks to strict physical distancing, a society may consider relaxing some measures (eg reopening schools). But you must be ready to re-impose drastic restrictions as soon as those critical numbers start to rise again, as they will, especially, paradoxically, in places that haven’t gone so bad so far. The restrictions should then be lifted and reapplied, and lifted and reapplied, provided the general population needs sufficient immunity against the virus. Trying to see our way through the pandemic with this ‘remove and lift’ approach is much like driving a car on a long and winding road. You need to hit the brakes and release them, over and over, to keep moving forward without crashing, all with your sights set on reaching the final destination safely.