Coronavirus. Walter Ricciardi (WHO): “We'll overcome this, but now is not the time to lower our guard"

Testing, tracking, "digital passport." These three points encapsulate the strategy envisaged by scientists and experts in view of "stage two", which, in line with the government's guidelines, must be implemented in two phases. The first would involve re-opening a few productive activities, while the second phase would entail adjusting travel and exit measures. The PM's new Decree is expected to be issued on Saturday, April 11, but experts call for caution so as not to undermine the efforts and sacrifices made over the past few weeks. "The epidemiological scenario - Walter Ricciardi, member of the Executive Board of the WHO, advisor to the Minister of Health for Covid-19 emergency, told SIR - is improving but it still remains critical. If it were a patient we would put it on the danger list. Despite the slowdown in new coronavirus cases, we can't take it off the danger list until the epidemic curve is flattened, i.e. when the rate of infections starts to fall.”

Professor, what should we expect in the coming weeks?
This is definitely not the time to let down our guard and to nullify all the sacrifices made so far;
in concrete terms, it means that Italians should be asked to stay at home for a few more weeks in order to plan a "phase two", to be implemented gradually and with a set of measures currently being analysed and assessed. But
first we need to see a significant reduction in the number of new infections.
Does it require a zero transmission index? 

We will probably only reach that stage with a vaccine that will produce an artificial population immunity, resulting in a transmission rate close to zero. Until then, the so-called "R with zero" (R0), i.e. the virus transmission index, will not be that low. For a certain period of time we will have to continue to live with this virus, but dealing with a just a few cases is not the same as having to deal with several thousands.

The "reported " cases seem to be just the tip of an iceberg in the face of a major flood. According to the Imperial College of London, 9.8% of the population is infected, amounting to 6 million people. You estimate as many as 20%. How many could they actually be?

A characteristic feature of infectious diseases is that the so-called “reported " cases represent only a small fraction. Many cases are not reported due to their very mild or even asymptomatic progression. Since this is a new virus, we don't know the extent to which the data are underestimated.

The actual circulation of the virus infection and the degree of immunity of the population will be known only by conducting a seroprevalence study on a representative sample of Italians, to figure out how far and wide the virus has spread and how many are protected by specific antibodies, i.e. how many have had the disease clinically or asymptomatically. 

What measures are you planning to put in place before easing the lockdown?  

I would summarize them in three steps:
testing, tracking, digital passport. 
Testing means extending the tests, not indiscriminately but in a targeted manner, first of all by performing molecular swabs on healthcare workers and staff in core businesses. But the early detection of cases, thereby limiting the threat of new infections, requires swabbing even those with mild symptoms, even in the presence of a single symptom such as a dry cough or some line of fever. If a person tests positive, a smartphone-app - pending voluntary participation - will start tracking the contacts of that person in the previous 48 hours. These people will be informed, without obviously revealing the identity of the infected person, so as not to violate their privacy, and invited to self-isolate and report the onset of symptoms at an early stage. An expert task force is working on this procedure, which would trigger a virtuous cycle.

Should those who successfully recovered at home, without any particular problems, be tested too? 

Yes, because clinical recovery often does not coincide with virological recovery. In hospital, patients are discharged only after testing negative twice.

How long can an infected person remain contagious after recovery?

We are not sure yet; some remain infectious for several days. The test is designed to determine whether those who recovered from the infection at home might re-infect.

You mentioned a “digital passport.” 

This strategy would enable the issuance of a so-called "digital passport", a "health certificate" to be inserted in smartphones, allowing healthy people to circulate freely .

The latest news is that rapid tests are being offered by several companies: what are they?

These are serological tests produced with no restraint and put on the market without a validation of effectiveness. EU law requires a safety assessment to be carried out, but not an effectiveness assessment, since their sensitivity and specificity are not validated. They must be used with great caution. The United Kingdom has purchased 17 million kits, which have proved to be completely unreliable. It will take some more time:

all the tests currently on the market, and even more so the rapid ones, are unreliable, unlike enzyme immunoassays, performed with sophisticated equipment and requiring much longer examination time.

How much longer will we have to wait for a specific treatment and vaccine?

The European Medicines Agency (EMA) is in contact with the developers of around 40 potential COVID-19 treatments; also the Food and Drug Administration (FDA) is in the process of evaluating a number of trials, but we have to wait for the results, which will not arrive before a few weeks or months, depending on the start time of the trials. Several vaccines are also being tested but the minimum time required for a vaccine is 12-18 months.

We will certainly overcome all of this, but we will need to remain vigilant for a long period of time. For now, we must not let our guard down. In "phase two" we will have to continue taking various precautions, especially social distancing.
Giovanna Pasqualin Traversa