02/05/2021 15:19
Clarín.com
Society
Updated 02/05/2021 15:53
In the middle of the debate about whether the contagion of coronavirus by touching a surface is possible, the Télam news agency spoke with the biologist
Emanuel Goldman
, professor at Rutgers University (New Jersey, United States) and with the Argentine virologist
Sandra Cordo
, who explained that there is
"little evidence"
of this transmission route, so that "efforts" should be put on the correct use of masks and ventilation, although they did not discourage cleaning and hand hygiene.
"
Little or nothing.
Only two or three possible cases in the scientific literature, but even these are not proven," replied Goldman, professor of microbiology at Rutgers School of Medicine, when asked about the evidence of contagion of the coronavirus by fomites or transmission by an "infected surface".
Already in July 2020, Goldman wrote an article in the British scientific journal
The Lancet
in which he warned: "A clinically significant risk of transmission of SARS-CoV-2 by fomites (surfaces or inanimate objects) has been assumed on the basis of studies that bear
little resemblance to real-life scenarios
. "
In that note, he carried out a review of the studies that had shown that the virus could
survive two and up to six days
on some surfaces, which for the specialist, was the product of two factors: a very high amount of virus and special laboratory conditions for its conservation.
"I am not discussing the findings of these studies, only the applicability to real life," Goldman wrote then.
"Finding the RNA of the virus is usually the same as finding the corpse of the virus. It is what the virus leaves after 'dying'. All it means is that the virus was there once, but is no longer 'alive' (capable of infect). This is
a fragile virus
that dies quickly in the environment and when it dries. Sunlight kills it almost immediately. Virtually all tests for live viruses (with infective capacity) when viral RNA was found, have been negative, "Goldman now explained to Télam.
In this regard, the virologist and researcher at Conicet Sandra Cordo stated that "there is considerable evidence of the presence (and persistence for many hours) of the viral genome on surfaces of various kinds (such as cardboard and aluminum) in experimental situations (simulated conditions in laboratories ), but
there are no data originating from real
contagion
situations
".
However, Cordo —who works in the Virology laboratory (Iquibicen-Conicet) of the Faculty of Exact and Natural Sciences of the UBA— argued that "this does not imply that we can
rule out contagion via fomites
, but we cannot know with certainty how many of the infections in real life are due to this transmission route ".
Regarding what it means to find RNA of the virus, the researcher explained that "it means that there is a genome of the virus, this represents a chance that there is an infectious virus, but it can also happen that there is not; many surfaces with RNA have been described in the scientific literature viral and
no infective virus
. "
For his part, Goldman described that the only scenario in which he considers that transmission by objects is possible is if someone touches
a freshly contaminated surface
(up to an hour or two after contamination), and then touches their mouth, the nose or eyes, also within an hour or two, without having washed your hands.
"But even that scenario is hypothetical," said the scientist.
Faced with the same question, Cordo was more cautious in her answer: "The possibility of contagion via surfaces occurs when infectious virus is deposited in it and the person puts his hand to his face, nose or eyes; there are studies of this in the laboratory, but
there are no documented cases of real life
that allow us to say specific times or conditions for that to happen. "
In addition, the specialist, who is a member of the Argentine Society of Virology (SAV), recalled that "there is data on the transmission of SARS-CoV-2 that has not yet been established and it is the
infective dose
; that is, the minimum amount virus needed (both on a surface and in an aerosol) for a person to become infected. "
This week, an editorial in the journal
Nature
also put the spotlight on this debate.
The prestigious scientific journal noted: "The SARS-CoV-2 coronavirus is transmitted predominantly through the air, by people who speak and exhale large droplets and small particles called aerosols. The contagion of the virus from surfaces, although plausible, appears to be
little common
".
And he questioned that the WHO is not clearer in its recommendations about where to focus.
In the article, the authors do not question surface cleaning, but caution that "individuals and organizations continue to prioritize costly disinfection efforts, when they could devote more resources to emphasizing the importance of
masks (chinstraps)
and investigating measures to improve
ventilation
. "
However,
frequent hand washing
remains a key tool to prevent the spread of this and any other virus or bacteria.
"All you have to do to prevent this possible surface pathway is wash your hands with soap and water after touching anything that may have been exposed to the virus," Goldman said.
Regarding the disinfection of objects, Corda said that "I would not advise against any cleaning measure, because in reality it is good that people have realized that
things from the supermarket can bring any type of disease
, since we do not know where they have been saved or who has touched them (for example, rats) ".
"The idea of adding care is important and knowing that there is another front that we must attend and that is that of aerosols. Everything would seem to indicate that
we can relax a little with the things of the supermarket
or with changing our clothes when we come from the street, that in May of last year he made us sleep, "he said.
"Today we have to put that energy into the use of
well-fitting
chinstraps
, in maintaining a distance of
two meters
and in ventilating closed spaces to take care of exposure to air potentially contaminated by viruses," he concluded.
Source: Télam.
LGP
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