Mixing Corona Vaccines.. what you need to know

It seems that mixing Corona vaccines will become the next question, said Dr. Catherine O'Brien, responsible for vaccines and immunity at the World Health Organization, that there are more than 17 vaccines that are currently used around the world, and that most countries have more than one vaccine that is used in the vaccination program against the Corona virus and its variants. .

In the 54th episode of the “Science in Five” program, presented by Vismita Gupta Smith, and broadcast by the World Health Organization on its official accounts on the communication platforms, Dr. O’Brien added that there is no evidence of the validity of what is being said that vaccines are similar, and therefore it is possible to obtain On one dose of one product and a different dose on another.

Two doses of mRNA vaccines

Dr. O'Brien explained that although no evidence has been found that most of these mix-and-match procedures are feasible, there is evidence that a first dose of AstraZeneca can be combined with any of the mRNA-based vaccines. , such as Pfizer and Moderna vaccines.

She explained, “What we do know is that a person gets a better response if they start receiving the AstraZeneca vaccine and then get the mRNA vaccine, or vice versa.

Both approaches can achieve a result and are a safe procedure. Regardless, there is still no evidence of the efficacy of other mix-and-match systems, as the results of the current trials of mixing mRNA and other vaccines have yet to come out.

And Dr. O'Brien added that the results of clinical trials, which combine the first dose of the AstraZeneca vaccine, the Pfizer vaccine, or Moderna, and then the second dose of the other vaccine, or vice versa, indicated that it is a safe procedure with regard to the amount of reaction on the arm and some short-term general reactions that can be achieved. That some are exposed, or that the fever is low-grade.

She noted that the safety guideline for blending mRNA vaccines is important because any recommendations issued by the World Health Organization must already consider safety standards.

Usual routine

On the issue of partial doses, Dr. O’Brien said that the procedure is not limited to Covid-19 vaccines, but is being tested for other vaccines as well, noting that the clinical trials conducted on these partial vaccines focused mainly on exploring what dose people should receive, and therefore The doses that have been circulated to date have been shown in clinical trials to provide very high protection against severe cases of Covid.

Dr. O'Brien added that WHO experts are aware that in the future there may be some evidence that says that there may be a need for booster doses, or that it is possible to lower the dose for some vaccines, in order to obtain better results.

Dr. O'Brien indicated that clinical research is currently being conducted to see if a small part of the usual dose can be effective, stressing that there is no answer to this question yet, but it is certainly an area that is being looked at carefully and experts expect that in the future the evidence will be reached. to whether partial doses or additional boosters are needed, and whether we should use the full dose currently being vaccinated as base doses, or whether a small portion of that dose should be obtained.

No to partial doses

Dr. O'Brien cited similar research, which has already been conducted on other vaccines to improve the results of their vaccination and the success of campaigns to combat anti-diseases, such as polio vaccines, yellow fever, and others, explaining that clinical research in this area is not new or has never been explored before with vaccines. Rather, they are steps taken for many vaccines to improve the amount of supply available and achieve the best immune response with the highest degree of safety.

She concluded by saying: “Therefore, waiting until the research in this area is mature and evidence-supported results become available, WHO scientific experts do not currently recommend fractional (or partial) doses.”