Mexico has already started crossing over COVID vaccines to apply third doses of AstraZeneca, and this is what science says about it


Reinforcements have arrived, not only in CDMX but also in Chiapas, Jalisco, Yucatan, Oaxaca and Sinaloa, where as of December 7. Third dose applications against COVID-19 for seniors only started, and in all cases are AstraZeneca vaccines, regardless of which biologics they have previously received from vaccinated people.

So officially Mexico began to cross vaccinations.

The case drew attention at the press conference to announce the CDMX booster vaccination, with the press directly questioning whether crossing the vaccines could be considered safe. The answer was not really given: State delegate for development programs for welfare in Mexico City, Estefani Correa, She saidIt’s even better that when Cofepris sets the guidelines and the health sector staff, they can talk to us specifically“.

Indeed, crossbreeding of vaccines is already an established practice given the lack of biological material and the intention of many countries to apply boosters, in some cases to at-risk populations, and in other cases more to the general population. Due to global interest, there are not a few studies conducted on the use of different biologics when applying a booster against SARS-Cov-2.

The vaccine mix has actually been a valuable resource before, such as when to start a vaccination Against HIV in the early 1990s. Now, studies involving AstraZeneca vaccines have essentially investigated the combination of the first two doses with a third dose of Pfizer or Moderna, since the latter works with the technology RNA رسول messenger, in contrast to the weakened adenovirus from AstraZeneca. Combining vaccines in this order was critical for many of the countries that responded by limiting the distribution of AstraZeneca after the EMA concluded that there was little risk of thrombosis in people vaccinated with the dose of AstraZeneca.

More and more antibodies

The result was much better than good. One of the most cited studies on this topic because it is powerful and is constantly updated, is ComCovStudy He received his PhD from Oxford University in mid-2021 is found Strong immune response in patients who received doses of Pfizer and Moderna after AstraZeneca. The study, however, considered schedules for the two doses, not boosters with a third dose included.

The same Oxford University has another ongoing study looking at the specific topic of reinforcements, and its name is COV-BoostAnd only on December 2, 2021 Posted His first data on the effectiveness of vaccines when using the cross in the third doses. The results are still mostly good news: the doses of RNA messenger vaccines such as Moderna and Pfizer-BioNTech that were used as a booster, led to stronger immune responses. However, there was a similar effect (albeit not of the same magnitude) when other vaccines were used as boosters.

Results published employment scalpel They came from a study of 2,878 volunteers who initially received two doses of AstraZeneca or Pfizer, and then received boosters from Johnson & Johnson, Moderna, Valneva, Curevac, Pfizer and AstraZeneca. The result was as expected: Moderna enhancers (which work with mRNA) elicited a greater immune response, but actually All doses induced an increase in antibodies and nearly all T lymphocytesThey are the line of defense that keeps a record of viruses and bacteria and in the event of infection again they are the first to initiate a chain of chemical signals that produce new antibodies.

Mexico has started crossing Covid vaccines to apply the third doses, and this is what science says about it

There is only one finding that can be decisive when it comes to evaluating the medium and long-term effects of vaccination with third doses of AstraZeneca: In the study, The only formulation that did not generate more T lymphocytes in the volunteers was the use of AstraZeneca as a booster after the first two doses also of AstraZeneca.. The Oxford University team says they will collect the information after three months and a year to see what effect that group will have so they don’t produce more T lymphocytes.

as a result of Investigation: “The relative role of T-cell immunity or immune memory is unclear, but may be of great importance“.

A booster is always a good idea

With these results, of course, increasing doses with mRNA seems like a good idea, but “If your country or region of the world has only one of the vaccines that we’ve shown can boost it, it shouldn’t be a problem to use it as a booster and it would be safe to do so” The She said Infectious Disease Specialist at the University of Southampton, Saul Faston, to New York times. Getting more antibodies with a third dose, even if no more T lymphocytes are being produced, is better than getting none.

Other countries that, such as Mexico, apply third doses of AstraZeneca are the United Kingdom and Australia, although they do so only in cases of Where mRNA vaccines are not available.

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