Rocio Magnani
02/26/2021 4:14 PM
Clarín.com
Society
Updated 02/26/2021 4:14 PM
The Buenos Aires Government confirmed to
Clarín
that
the second dose of the Oxford-AstraZeneca Covishield vaccine
, with which the immunization of adults over 80 years of age and people living in nursing homes, will be administered by the City
with an interval of 10 to 12 weeks from the first application
, and not at four weeks, as had been reported in vaccinations and nationally.
"All those who are now being vaccinated against Covid-19 will have to wait
between 70 days and 84 days to have their second dose,"
said the Undersecretary of Primary Care, Gabriel Battistella, and explained that, although the last application of Covishield can be carried out after 30 days, "the studies that exist so far say that the more distance there is between each application,
the more effective the vaccine is
".
In this way, the adult over 80 years of age who received the vaccine on February 22, when the campaign began for this population group, must wait at least until May 3 and, at most, until May 17 to receive the second dose in the City of Buenos Aires.
The term that the vaccination will take "will depend a lot on the vaccines that the City receives," Battistella clarified.
"
If we start with Sputnik-V in older adults, there
will be 21 days
" interval between each dose and the immunization of each person will be complete in a shorter time, he clarified.
"We have already applied
15,000 doses of Covishield in older adults
, with few adverse reactions," the official reported and said: "The doses are few, but we are doing well."
Horacio Rodríguez Larreta's administration expects “a large quantity” of Covishield doses to arrive in the coming weeks, to complement the first batch of
40,000 units
.
The undersecretary denied that the decision to vaccinate after 10 weeks of the first dose is unchecked from what is established by the ANMAT.
"The national Ministry of Health says that you can apply the second dose of Covishield from four to 12 weeks and
each jurisdiction establishes the rhythm based on those guidelines
from which you cannot differentiate yourself," he explained.
In addition to the question of efficacy, this modality may allow
"more people" to get vaccinated with the first dose
before having to start the second, Battistella argued, adding that it also allows time for further advances in vaccine studies. : “Perhaps in the next few weeks a study will come out on those people who had Covid and who have significant levels of antibodies with a single dose.
It is something that we do not know now, but there are already several investigations developed and
perhaps even the second dose can be avoided
”.
How much does the effectiveness vary?
Covishield vaccine is manufactured by the Serum Institute in India, one of the largest vaccine companies in the world, which produces it under license from Oxford-AstraZeneca.
"It is a vector vaccine that uses a chimpanzee virus as a vector and has a combined efficiency of 70%, which according to
the studies and the doses ranges from 60% to 90%,
"
the infectologist and presidential advisor Eduardo López
told
Clarín
.
“It is a vaccine that the WHO and the European Medicines Agency (EMA) have approved from 18 years of age, although Germany and Spain have not approved it for people over 60 because they say that
the studies for that age are not finished
”He continued.
Like Sputnik-V, which has a combined efficacy (with the two doses) of 91.6%, Covishield also requires two doses - in the case of Sputnik they are different from each other, while AstraZeneca is the same formula- .
But while with the Russian vaccine, mainly aimed at health workers so far, the time to apply the second dose is between 21 and 60 days after the first application, the second dose of Covishield is indicated between 28 and 84 days, the specialist detailed.
Along these lines, he continued, while with AstraZeneca some countries “prefer to maintain the dose interval as it is approved in phase III of the study, which is from 28 to 30 days, the committee of experts from England proposed to extend it to 12 weeks, based on a study that says that, by spacing out the interval,
the vaccine could have a higher efficacy rate
”.
The study, for which the University of Oxford intervened, as well as authors from the University of São Paulo and also from South Africa, establishes that applying the second dose of Covishield at 12 weeks, "the efficacy of the vaccine studied at 14 days from that second dose it
rises to 82%
, while when you vaccinate between 9 and 11 weeks, the efficacy is 63% ”, he explained.
Regarding the first dose, "it was seen that the efficacy with a single dose of AstraZeneca vaccine from 22 days to 90 days post vaccination was 76%, and that the antibodies remained stable in this period of 90 days" added.
López asked to relativize these percentages.
“It must be said that the combined efficacy of 70% for the Oxford-AstraZeneca Covishield refers to a global efficacy, both for mild, moderate or severe cases of Covid-19, but the vaccine has a very high efficacy,
greater than 90% for the most serious forms of Covid-19
.
It is not the same as an older adult acquiring a catarrhal or flu from Covid-19 than having to be hospitalized, "he said.
The Argentine doctor Marta Cohen, who lives in the United Kingdom and from there has been following the progress with the AstraZeneca vaccine very closely, also
supported the decision to apply the vaccine after week 10
.
“In Brazil and South Africa, while the study was being done, the second dose had not arrived due to production issues.
So some were given it at four weeks, others at six, others at 12. The researchers were
transparent
, explained this and analyzed the results and saw that immunity is higher between week 8 and 12 ", Cohen explains.
For her, it is also a good measure to use the available doses to
vaccinate more people with a single application
.
“If there are 10 million doses, vaccinate 10 million people and not five.
That was the criterion that was applied in the United Kingdom, where daily infections fell from 68,000 to 8,000 per day, "he remarked.
ACE
Look also
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