Pablo Sigal
04/09/2020 - 12:01
Clarín.com
Society
"Recontrastables".
That is the diagnosis of the City of Buenos Aires when it asks how the epidemiological situation of the coronavirus is.
It describes a scenario that has occurred since mid-July: there were
three spikes of infections
.
The middle one was in early August (the most important so far) and the third last week.
The balance is that, despite the ups and downs,
it always returns to the same waterline.
The so-called R (contagious index) had remained
below 1 for 12 days, until last week
.
That meant that more infected infected fewer people.
It reached 0.95.
But then there was a new rise above the unit.
Four days ago the index returned
to the desirable zone again.
According to those who work side by side with the Minister of Health, Fernán Quirós, he calls it the
“dromedary effect”
, due to the way the pandemic has been taking in the City in recent weeks.
One week up, one week down.
Peaks and valleys.
The maximum peak so far was recorded
at the beginning of August
, although they do not rule out that another may occur later.
Caution prevails.
There is
"green button"
, but with one hand on the "yellow button".
There are elements that reassure the Buenos Aires authorities.
They have developed a measurement model called
"Moving
average
of the last 7 days"
, by which they take a weekly average but on a rotating basis.
That way they think they can have a better idea of how the curve behaves.
Based on this methodology, they see a
controlled scenario: between a thousand and 1,300 cases per day.
This Thursday the City counted
1,411 cases
, a little more than that average.
And last week there were also days with some top marks.
They offer two explanations for these “exceptions”: the last week of August some infections from previous days were loaded into the system.
And most importantly, there is an incidence in the final number of those called
asymptomatic.
One of the last Buenos Aires reopening: bars on the sidewalk.
Photo: Andrés D'Elia.
The asymptomatic
are the key
to this pandemic.
There are many.
They are the ones who put Italy and Spain in check, for example.
When they realized there that the virus was circulating, it was too late.
There is no district in the country, except the City, that is currently
looking for asymptomatic infected people to isolate and cancel them
as links in the chain of contagion.
These asymptomatic are detected through
saliva tests
.
They are PCR, but less invasive.
They do about 400 a day and
18 percent test positive
.
How do they get to them?
They go to the houses where they already know that there was an infected person and they test the whole environment.
It is a plan that takes three weeks.
That the Buenos Aires curve remains stable is due, in part, to this
proactive search
, instead of waiting for cases to appear spontaneously.
The "recontrastability" of Buenos Aires is also reflected in the
occupied intensive care beds
: a month and a half ago there were 280 occupied beds.
On Wednesday night there were 264. The peak of occupancy occurred with the peak of the curve in early August, with 300. These are data from the public health system.
This whole panorama is the one that poses a quite different scenario, at least in the City, from the one that President Alberto Fernández has been observing at the national level, when he
threatens to press the "red button"
and re-adjust the confinement.
The question, anyway, is what would be the margin for people to comply, after six months of pandemic and
169 of quarantine
.
The Buenos Aires "green button", on the other hand, is the product of this conclusion:
"It is impossible to link any fact with anything"
.
What does it mean?
This "dromedary effect" that the Buenos Aires curve draws is what, according to the City authorities, allows to affirm that there is independence between the administered quarantine openings and the perceived health effects.
A complementary piece of information, and that will help to have a more complete notion of the Buenos Aires pandemic scenario, is the
seroprevalence study
.
It will allow knowing how many people in the district had Covid and did not find out.
They will find out through a blood test because they
have developed antibodies
after having had the disease asymptomatically.
The study took longer than expected.
According to the original plans, the results should already have been, but methodological issues prevented it.
It's like this: they search for people at random in different neighborhoods.
And what happened, basically, is that the neighbors who were in the houses
were not the right ones to test
, because they did not go out or they went out little.
Those who were the right ones were working.
Now they are in that instance of "hunting them" at other times.
They think it will take two more weeks.
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