Paula galinsky
08/29/2021 4:14 PM
Clarín.com
Society
Updated 08/29/2021 4:14 PM
The first news from China spoke of a virus that exceeded the usual parameters.
Then we understood that in addition to the variant of the place where it had originated - in Wuhan - the Covid 19 was mutating and was generating
new variants of concern
.
Among them, Delta.
Vaccines with different technologies appeared, although all created against that first version of the coronavirus.
Today, the possibility of a third is added to the two doses and the options worldwide are diverse:
combined vaccines, improved doses
and even a
nasal spray
to advance the prevention of contagion.
The specialists consulted by
Clarín
they answer about the chances of developing new mutations and the way forward in relation to vaccines.
“In the evolutionary process of the virus, mutations have already arisen and
new ones will surely continue to appear
,” says Horacio Salomón, biochemist, doctor in Virology and senior researcher at Conicet.
Against them, it is likely that next year "
some vaccines will be adapted
so that the escape of the immune response is less".
“This does not mean that the available vaccines stop working.
I don't even think that the development of a new vaccine is so relevant today, although there is a possibility that the famous third dose will
come with some improvement
, for example against Delta ”, he says.
In this vein, Pfizer announced that it is
manufacturing a vaccine against the Delta variant
.
However, the CEO of the pharmaceutical company, Albert Bourla, told the American television network NBC that he does not think it is necessary.
"The current vaccine against Covid 19 works very well against the variant," he contributed in this regard.
Electron microscope image of SARS-CoV-2, the cause of Covid-19, emerging from the surface of cells.
Photo EFE
The important thing about that third dose, according to Solomon, is that it works as a
booster
and raises the levels of neutralizing antibodies so that, in case of infection, the body eliminates the virus quickly.
“There is still no concrete data on when it would be convenient to receive this vaccine.
A good idea would be to guarantee a
generalized reinforcement one year after the second dose ”, he details.
And he explains that it is not clear
what will happen after Delta
, especially if other mutations arise that evade the body's ability to defend itself.
“It is very difficult to make predictions.
The key now is to
complete schemes
, that is the way to prevent the virus from replicating on a large scale and, consequently, from continuing to mutate ”, he adds.
Strains and variants
For Belkys Maletto, biochemist, doctor in Chemical Sciences and researcher at Conicet, it is not so easy to refer to the future of the coronavirus. "Although analogies are made between Covid and Influenza and that is why at some point there was talk of the possibility of offering a different vaccine each year, the truth is that
the coronavirus behaves in a very
dynamic and unexpected way
and we still cannot specify what will happen ”.
Most of the vaccines developed so far are focused on protein S (
spike
) or even on a part of that protein which is RBD.
It is that this is the
access route of the virus to the body
: through the spike of the coronavirus is that the virus binds to the receptor of the cell and infects it.
"That key with which the Covid tries to enter was slightly modified in order to evade the immune system.
For a new vaccine to be necessary, a variant would have to emerge that drastically changes the S protein, that would be almost like facing a new virus ", he remarks and points out that he considers it" unlikely. "
Vaccination at the headquarters of La Rural in Palermo Photo Rafael Mario Quinteros
He agrees with Solomon that the available vaccines are effective against the mutations that are known to this day. It also warns that most of the conclusions about the new variants and the immunity generated by vaccines are drawn on the basis of the humoral response (neutralizing antibodies). "And that is not the only defense we have," highlights the expert, who is a professor of Clinical Biochemistry at the Faculty of Chemical Sciences of the National University of Córdoba.
“The
cellular memory response
is not usually considered because it is more expensive to measure.
But it should also be taken into account as a useful tool ”, he highlights.
It refers to B lymphocytes, which are used to recognize the virus and generate antibodies, and T lymphocytes, which develop a series of molecules capable of attacking the coronavirus.
“There is a study done on T lymphocytes that shows that
its scope
does not change with the emergence of new variants
of concern ”, he comments and quotes a work published in the journal
Cell
in July this year.
Alternative vaccines
According to Maletto, one should not think that salvation is in a new vaccine.
“Certain details can be adjusted for a third dose, although that third dose can also be reinforced by the hand of
heterologous vaccines
.
For example, that a person who received two from Sinopharm adds a reinforcement from Pfizer ”, he summarizes.
And he adds: "Even before the coronavirus, it was known that combining different vaccine platforms translated into an improvement in the quantity and quality of antibodies."
He says that certain vaccines can be refined, although he assures that it is impossible to keep up with the Covid: "It is not rational or practical to modify vaccines every two or three months, which is the time when a new variant emerges."
The other limitation, according to Maletto, is that there are still countries without even a dose. “The World Health Organization (WHO) has already said, it is not advisable to give the third dose to some when
there are others who have not yet received the first
. And not only because of the consequences on that unprotected population, but also because in those territories where the virus circulates freely, the chances of
new significant mutations arising are
greatly increased
”, he confirms.
The element that could make a difference for the specialist is the development of a nasal-administered vaccine.
“There are already clinical trials, although they are pending approval.
It would be one more step to achieve
immunity in the upper airways
and thus advance not only against serious disease but also on the prevention of infection ”, he closes.
MG
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