Irene Hartmann
02/22/2021 17:12
Clarín.com
Society
Updated 02/22/2021 18:03
Until Sunday it was circulated that this Thursday night the largest batch of vaccines would arrive in Argentina since the long-awaited stage of immunization against the coronavirus began: one million doses of the
BBIBP-CorV
vaccine
, better known as
Sinopharm
, the name from the Chinese company that produces it, in collaboration with the Beijing Institute of Biological Products.
This Monday, sources from the aeronautical sector explained to
Clarín
that Thursday seems a
difficult goal
, since at the end of this note there was no confirmed departure flight.
But, delays aside and considering that the largest infectious disease specialists in the country indicate "
do not hesitate and get vaccinated with whatever
”, It is worth reviewing the particularities of this drug.
It is that both Sputnik V and the Indian version of the Oxford-AstraZeneca (Covishield) use a technology - "platform", experts like to say -
completely different
from Sinopharm.
As described by the infectologist and main adviser of the Government in the pandemic,
Pedro Cahn
(medical director of Fundación Huiuda and who carried out the local study of this Chinese vaccine, for which 3,008 volunteers were recruited), “the Sputnik vaccine uses two types of adenovirus, a virus that causes colds.
These viruses were genetically modified and placed in an antigenic element: the gene for the Spike protein.
In this way, the body builds antibodies.
In the case of
Sinopharm, the Covid-19 virus was used, but dead, that is, inactivated
”.
There is a lot of talk about antigens.
What are they?
The packaging of the Chinese Sinopharm vaccine, of which one million doses will arrive in the coming days.
/ Asim Hafeez / Bloomberg
Jorge Quarleri
, PhD in Biochemistry, expert "virologist" at the Institute for Biomedical Research in Retroviruses and AIDS (INBIRS) and Principal Investigator at Conicet
explained it with accessible words
.
“
An antigen is any substance capable of generating an immune response from the organism
.
To make an inactivated vaccine, the virus is multiplied in the laboratory and then purified.
By means of a chemical treatment, it is inactivated in order to cancel any possibility that this virus is viable: it will not be able to multiply and it will lose its ability to infect ”, he clarified.
"Once inactivated, you get a
bag of viral antigens
. This is different from the vaccines that have been used so far, which immunize with a particular antigen, the
coronavirus
protein S
," Quarleri said.
The three experts consulted (and this includes
Juliana Cassataro
, specialist in immunology, infectious diseases and vaccine development at the Institute for Biotechnological Research of UNSAM) agreed that the inactivated virus platform is "classic", and that it is used in several vaccines of the official calendar (such as the one that fights hepatitis A), since it is suitable, in terms of "safety", for all types of patients, including
immunosuppressed and pregnant women
.
Another advantage is conservation, which facilitates all the logistics of vaccination: it is well maintained between 2 and 8 degrees, that is, the temperature of a common refrigerator.
As for the doses, it does not differ from other vaccines: they are two, identical, separated by three weeks.
The against?
The cost.
Although the Sinopharm vaccine uses another platform, it is given in two doses, just like Sputnik.
/ Asim Hafeez / Bloomberg
Before we get to that point ...
is it better to get a coronavirus vaccine that has a lot of antigens?
First, Cahn said, "in terms of the perception of the recipient, there are no differences."
Although the results of the local study with this vaccine are not ready, “international data indicate an
efficacy of almost 80%
.
In addition, the adverse effects are minor - some fever, perhaps, and a little pain at the injection site - and the main thing is that it works by preventing
serious forms of the disease
.
With these words, Cahn raised a central question:
there are
still
no studies that prove that any of the dance vaccines is capable of completely preventing the spread
of coronavirus.
On the other hand, it is known that the chances of having severe symptoms in the face of the disease decrease.
These are subjects under study and, just as the famous paper on phase 3 of the Sputnik vaccine was long in coming, there are also missing publications of that phase of the Sinopharm vaccine, beyond the fact that the ANMAT recommended it for emergency use and the Ministry of Health authorized it.
Horizons
For Juliana Cassataro some optimistic hypotheses can be put forward regarding the developments with inactivated virus: “The Chinese vaccine, unlike the others, has all the coronavirus antigens.
From an immunological point of view, in the long term, these types of platforms
could be less susceptible to the changes that the virus naturally makes
.
But you have to wait.
For now it is not really known ”.
The cost of a supposed benefit is clear.
“The development of these vaccines
takes longer
, and that's why drug companies often choose adenovirus.
To make an inactivated virus, a plant is needed to manufacture live virus, with all the safety conditions, which makes production much more expensive, especially with these very dangerous viruses.
That is why they
are more expensive vaccines
”.
Vaccination of adults over 80 years old, in La Rural.
Photo: Luciano Thieberger
And enough.
Of the between 4 and 10 dollars per dose that was handled, we reached an agreement that is around
20 dollars per dose
, after a reduction that Argentina achieved.
Maybe it is worth the expense.
According to Quarlerí, "the only neutralizing antibodies are those that the body develops against protein S, but using an inactivated vaccine will achieve antibodies against other viral components, whose biological significance we still have to elucidate in terms of protection."
There is also another immune response of the organism that could be amplified with this type of vaccine: the immune response mediated by T lymphocytes, "which is the organism's cellular response. The immune response could be prepared to recognize in a more extended way the presence of infected cells ”.
However, the expert said, "as with all vaccines, you have to be cautious: wait for the end of phase 3 and do pharmacovigilance for a long time."
$
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