Epidemic, where’s the virus gone? Empty intensive care units and a point of view

11.06.2020 – 10.00 – Italy has completely reopened and things are going very well, from an epidemiological point of view.
There are a few issues, however, that need to be clarified. There is some controversy as to whether the virus has mutated or disappeared, whether it is suffering because of the high temperatures or whether, on the contrary, it is still around, as in fact it is.
In reality, in the immediate future, these questions are not fundamental and ultimately of little interest: they can be left to scientific speculation and journalistic interpretation.
Every living species tends to create and enlarge its ecological niche.
The host- pathogen interaction can be considered a predator-prey relationship and in the natural environment predators regulate the number and geographical distribution of prey.

Both predator and prey possess weapons to guarantee their own survival: the virus, for example, has a rapid reproduction time, carries out gene exchanges and antigenic mutations.
Man has non-specific species resistance, an efficient immune system and his intellect. Now, in a very pragmatic way, since it is not possible to give a precise and certain answer on what is really happening to the virus, we have to stick to assessments based on observation. These tell us that people, even if they get infected, get much less sick than in March and April and so they do not require hospitalization, and in many cases not even the intervention of a practitioner and of an ambulance.

The number of cases decreases, the number of recovered patients increases, the number of hospitalizations decreases, ICUs are almost empty and there are fewer and fewer people in isolation at home and these are irrefutable data.
Another open question is whether and when there will be a second epidemic wave. Myxoviruses are the flu viruses and are the ones that give the usual seasonal epidemics. The current pandemic is caused by a completely different virus, belonging to the Coronavirus family. Myxovirus and Coronavirus are two very different families of viruses in terms of characteristics, transmissibility, attack rates and lethality.

It follows that being a Coronavirus the infecting agent of the current pandemic, there is no objective element to predict or assume other epidemic waves in 5 or 6 months or a periodic annual frequency linked to seasonality as happens with influenza. Today no one can predict whether the Coronavirus will have a similar pattern, but it does not seem likely.
It seems that the spread of the virus is also influenced by temperature and humidity; the infection would spread more rapidly at temperatures of about 5°C and medium to low humidity. Conversely, in very hot and humid climates, the epidemic would be less severe. Now, in the southern hemisphere it is late autumn and in less than a month it will be winter, with the certain reappearance of the flu epidemic caused by the A H1N1 strain (Influenza Myxovirus).

If Covid-19 had a similar trend, there would be an increase in cases in the coming months in South America, South Africa, Australia and New Zealand. We just have to wait and see.

In order to deal with the restart phase in Italy, we must focus on individual responsibility and information. In our country we have had three epidemics: one in Lombardy that unfortunately is still going on, one in the rest of the North, a little more moderate in Piedmont, Veneto, Emilia Romagna and Trentino, and another one in the rest of the national territory.

The Coronavirus is transmitted by the respiratory route and therefore the only effective preventive measure is the distance between people. The surgical mask increases the protection of others, if we are infected, and in closed and crowded places it is certainly still recommended, but it should be changed after 4 or 5 hours. The effective anti-contamination measures are, and remain, three:

1. Social distancing;
2. the use of masks;
3. hand washing.

There is a misunderstanding between sanitization and wash-disinfection. It is necessary to distinguish the health care environment, the hospital, the home, the workplace, the playgrounds.
The needs, clearly, are different and are not the same. The WHO states that it is enough to wash tables, chairs and desks every day as before. The 5% bleach solution is cheap, you can buy it anywhere and it is very efficient. Ozonization, UV-lamps, scented quaternary ammons, are all measures not suggested by Evidence Based Public Health.

What you need is to wash the surfaces thoroughly: in fact, disinfection is useful only after a thorough wash. Airing the rooms is also a simple and very correct practice. The atomisation of outdoor environmental disinfectant is not recommended, outdoor areas generally require regular cleaning and not disinfection. Spraying disinfectant on pavements and in parks is not proven to reduce the risk of infection with Covid-19.

The probability of becoming infected by touching surfaces, objects, computer keyboards, seats, handles, shopping bags or clothing is infinitely small in real life. Sars-CoV-2 is a respiratory transmission virus and an infected, even asymptomatic, emits billions of droplets by breathing: the micro-droplets of water vapor that can also carry epithelial cells. These droplets remain suspended in the air for some time and then settle on the surfaces surrounding the infected person.

Some of these droplets also contain cells where there is an active virus replication. There is therefore a remote chance of contaminating your hands with these fresh droplets before they dehydrate and their contents are inactivated. The virus is not transmitted by the skin or orally, in fact the saliva itself inactivates it.

However, there is still an unlikely possibility that, after the concomitant realization of all the events described, a person could rub his eyes, allowing the introduction into the body, of cells in which the virus is still replicating, by conjunctival route. One understands how getting infected by collecting the virus from a surface requires a sequence of exceptional, rare and unfortunate combinations. In fact, the survival of Sars-CoV-2 under these conditions has been demonstrated, in experimental situations, only for traces of viral RNA, but not for the whole virus. However, the viral load must be composed of millions of viral replicates, it cannot fall below a certain threshold to be infectious.

Last notation on the indiscriminate use of latex gloves by the general population: their use is recommended in healthcare environments, not for the public. The usual use of latex, rubber or cellophane gloves causes problems; they collect and transport cells potentially infected by the virus, just like bare hands, but, unlike bare hands, you cannot wash them, they also cause annoying perspiration and must be removed correctly. In the surgical-health sector, on the other hand, they are essential because the professionals directly touch biological materials.

Finally, we must consider the environmental damage that the disposal of these quantities of disinfectants, plastics, bags, used masks and gloves causes. When an epidemic is detected, which is neither immediate nor obvious because it requires the accumulation of observations and intersections of health information, it means that the virus has already been circulating for some time in the general population. It is therefore necessary to invest in the territorial services of Public Health to identify, isolate and trace the contacts of the suspected infected person. These are the ‘3 Ts’ – Testing, Tracking and Treating – of field epidemiology, indispensable to be ready and equipped to react routinely, at any time and with very little notice, to face future challenges.

Author: Fulvio Zorzut

Michael Guggenbichler translation