The latest bulletin confirms the constant increase in positive cases, which have exceeded 53 thousand. Yesterday 2,499 new infected were counted, compared to a record number – 120,301 – of tampons processed, 23 deaths of Covid-19 patients, with several deaths in RSA, 48 more hospitalizations and almost 300 beds occupied in intensive care. Not only that: in the Center-South they are reported more and more healthcare facilities under stress and Covid has also raised its head in Veneto. How worried can this trend be? What is the South at risk? Where are we with herd immunity after more than seven months of epidemic? Is the virus back as aggressive as in February-March? Do we have useful therapies to face this new outbreak of Covid? We asked Antonio Clavenna, researcher at the Mario Negri Institute’s Department of Public Health.
In the Center-South the virus has started to run again and there are strong pressures on health facilities. Why are the regions of the South at risk?
It is possible that in contexts that did not experience a tragic impact with the virus in March-April, as in some contexts in Northern Italy, such as the province of Bergamo, people tend with greater difficulty to systematically adopt certain preventive measures. The time has come to change daily behaviors and to be more cautious. This does not mean giving up completely on normality, but more attention does.
Could they find themselves in the same conditions in which the northern regions found themselves in March-April?
The problem in the southern regions – and the concern was already present last spring – is the level of health infrastructure and availability of hospital places that are lower than in the north. Some southern regions, even with a less intense epidemic than that experienced in Lombardy in March, could suffer.
How to avoid this risk?
It lies in the ability to promptly implement measures at the population level that allow the circulation of the virus to be slowed down: greater attention to physical distancing, to the use of masks when and where it is necessary and to hand hygiene. This slowdown may allow health facilities to cope with infections and hospitalizations with less trouble.
So should the obligation to wear a mask even outdoors be adopted everywhere, and not only in certain areas with a strong growth of infections?
In my opinion, no. Contagions in the open air are much less likely than in closed places. It would mean imposing an obligation even in poorly urbanized contexts and the possible advantage in terms of epidemiological control is not so high. The biggest problem is that even today there are many situations, for example in the workplace or in public places, in which there is not due attention to follow the rules.
Is it possible, on the other hand, that in Northern Italy we are no longer going back to the times of the hardest emergency?
It is likely, because we are more ready to face the situation, as we know that the virus is circulating. In February-March, when in Lombardy, Veneto and Emilia-Romagna it was realized that Covid was present in the population, it was a surprise, especially for the extent of the people infected. We were caught off guard and this wave swept the health systems.
Today?
There is a level of attention, planning and the possibility of implementing containment and contrast measures. Even if the numbers increase, I think the situation shouldn’t get out of hand.
Seven months after the discovery of the epidemic, what evidence do we have on immunity? Is it true, as claimed by a survey by Gimbe, that Lombardy can be considered the most “protected” region today?
Could be. But two factors must be kept in mind. On the one hand, the known data: a serological survey conducted by Istat and the Ministry of Health tells us that Lombardy is undoubtedly the region with the largest number of people, 7% – but there are areas of the region in whose prevalence is close to 50%, as in some towns of Val Seriana, in the Bergamo area – which they developed antibodies. You pointed out that the figure is not only lower than what was expected at the beginning, but it is also far from what experts indicate as the threshold, equal to at least 60-70%, to achieve the so-called community immunity or immunity. of herd.
The second factor?
Some researchers speculate that not only antibodies create immunity against the coronavirus, but to some extent also the cells of the immune system, for example T lymphocytes, can guarantee protection, because, while not specific against Covid, they are able to recognize a similar virus, for example that of the classical flu, or they are activated for vaccinations.
What does this mean?
Given that, even in the presence of laboratory data to this effect, the theory has yet to be confirmed, if we add this non-specific cellular immunity to the antibody immunity, which allows the body to give a more prompt and effective response to viral aggression , it is possible that in some areas of Lombardy the population somehow protected from the virus could be around 60%.
Could this hypothesis therefore explain the high incidence of asymptomatic or paucisymptomatic patients?
It is a contemplated hypothesis. We are still learning a lot about this unknown or little known virus.
Is the virus still as infectious as it was in spring?
A distinction must be made. For virologists, the characteristics of Covid have not changed much, to the point of making it less capable of spreading and infecting people; the infectious potential is the same. Community dynamics change.
That means?
If implemented, the planned containment measures, including greater use of smart working which reduces mobility and opportunities for gathering in indoor places, from public transport to offices, impact on the possibilities and probabilities of transmission of the virus. Therefore, with the same viral load, the virus is less likely to spread quickly.
Positive cases have returned to the levels of five months ago. Is the surge due to the reopening of schools and this summer’s holidays and nightlife?
The previous growth, calculating an incubation of two to three weeks, is certainly related to the holidays. In these days, however, the first fallout from the reopening of schools could be observed. However, let us remember that the data of the single day does not have much value, it is very influenced by the number and geography of the swabs processed. Better look at the weekly trends. But an increase in infections was widely expected, it shouldn’t frighten excessively. The type of population that is infected should be monitored: if the virus affects children and young people, the impact on the health system is of no concern and the risks for infected subjects are low. A completely different speech if the infection affects the most fragile subjects. At the moment, the situation in hospitals and intensive care units is fairly under control in many regions. A sharp increase must absolutely be avoided.
The pandemic numbers focus on positive cases, ICU patients and deaths. But what does the trend of the healed, of which little is said, tell us?
The trend is positive and we know that most people recover when they do not have the symptoms of the acute phase of the disease. There is no emphasis on the healed, because the focus is obviously on the indicators of attention and alarm. However, it is emerging that in some people recovered after the acute phase there are consequences and damage that can even last months.
Despite not having a specific anti-Covid drug, can the set of therapies available today be considered effective and reassuring?
We have quite effective and by the way known drugs for some time. The therapy that appears most effective, in patients with the most severe symptoms, is that with cortisone drugs, which reduce the chances of death.
Wasn’t it remdesivir?
It is an antiviral that can be useful against virus infection, but its effectiveness is not exciting: let’s say it helps reduce the duration of the disease by a few days, but it does not seem to have an impact on more important clinical indicators, such as risk to be admitted to intensive care.
One study re-evaluated the role of hydroxychloroquine. What do you think?
The studies that demonstrate its effectiveness in terms of reducing the length of hospitalization and the risk of death are, at the moment, only of an observational type. More solid studies agree that hydroxychloroquine is not very beneficial.
In Italy, the first case of flu was discovered in a 9-month-old baby in Parma, in advance of the usual arrival of the flu. Does this push us to anticipate the vaccination season?
The decision to anticipate the flu vaccination campaign has already been taken and will start around mid-October. However, it is not so unusual that the first light and sporadic symptoms of the flu appear in early October.
Is it true that flu vaccine, pneumococcal vaccine and tuberculosis vaccine can help defend against Covid?
Some vaccines, and some more than others, such as tuberculosis, measles, mumps or rubella vaccines, could reduce the risk of contracting Covid-19, because they stimulate cellular immunity. But even in this case the data are not conclusive. And on the pneumococcal vaccine the results are mixed. The benefit of flu vaccination could be especially for people at risk, because it would prevent them from contracting both the flu and Covid-19 at the same time, which would be extremely dangerous.
Speaking of the anti-Covid vaccine, after the decision of the European Medicines Agency to start the trial of the Oxford vaccine candidate, should we expect positive news soon?
Compared to the times, it is difficult to make predictions. The Agency’s decision is a first step, it will take time to get the authorization, also because some advanced studies are still in progress. I agree with WHO estimates: the vaccine will not arrive before mid-2021.
(Marco Biscella)
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