We provide three vaccines against covid-19 in Spain, two of which are based on nucleic acid technology (Pfizer-BioNTech and Moderna) And another using a viral vector (Oxford-Astra Seneca), which contains the same antigen, the so-called S protein or special protein, which is the fingerprint that our body must learn to recognize and neutralize when facing real viruses.
However, we have no data to Direct comparison These vaccines. The vaccine efficacy data in question-95%, 94% and 70% respectively-cannot be directly compared. Each vaccine has been studied at different places and times, and the populations and circulating strains are different, and even the relevant research has not been completed.
When the minimum requirements are met, an intermediate analysis can be performed so that it can be evaluated and obtained by the regulatory agency Emergency use authorization. Therefore, we cannot determine whether these three vaccines are good or bad in terms of efficacy, because the data from these studies cannot be directly compared with each other.
But even if we did, I insisted that it should not be done. From a mathematical point of view, when we consider their values, it is impossible to say that these values are indeed different. Confidence interval. The 95% confidence interval is the range of values within which the efficacy of the vaccine is found 95 out of 100 repeated studies. These intervals overlap between the three lenses.
In the latest analysis of the AstraZeneca vaccine, the estimated efficacy has increased from 59% to 70%, and if the interval between two doses is 12 weeks, it can be increased to 80%
In addition, clinical trials are not over yet, so as new cases accumulate in vaccinated or placebo patients, these efficacy numbers and their intervals will change. The latest example comes from the latest Oxford-AstraZeneca Vaccine Review, where a 12-week interval between dose estimates increases the efficacy estimate from 59% to 70%-if the data accumulated in one month is added, the efficacy estimate is increased from 80 % Increased to 80% of the study.
Normal discomfort of any vaccine
This Accumulated experience After more than 200 million doses worldwide, the drug was very positive and reiterated the safety profile that has been observed in clinical trials, Usual troubles Related to vaccination, it may be more common than other common adult vaccines (such as influenza or pneumococcal), but it is also benign, short-lived and self-limiting.
On the other hand, although the efficacy we have measured in clinical trials does not have to be the same as Effectiveness in the real world The so-called effectiveness, the preliminary data of large-scale application is very positive, and it also confirms the high-efficiency numbers observed in clinical trials.
Why not wear clothes of any age?
This Upper age limit The use of the Oxford-AstraZeneca vaccine raises understandable doubts and is certainly difficult to overcome because although there is no reason to panic, the explanation is not simple.These decisions serve The needs of each countrywith Availability of other vaccine doses, Which can establish an internal priority strategy for some vaccines, but not others.
Using AstraZeneca, published immune response data indicate that there should be no difference in clinical efficacy in the elderly
They are temporary measures only due to the fact that efficacy evaluations for the highest age group have not yet been obtained, and there are already other vaccines in our country that have this information.
Why don’t we have these results yet? Well, this may be due to not having enough time among other factors. Lower proportion of elderly patients Include in the study, or to protect participants in these age groups to a greater extent, so the necessary cases have not yet been accumulated to be able to calculate the efficacy of this age group.
However, published data on immune responses indicate that there should be no difference in clinical efficacy among the elderly. In fact, the WHO, European Medicines Agency and the United Kingdom have not set an upper age limit for the use of the Oxford-AstraZeneca vaccine.
Also talked about Different operations Based on these new vaccines, genetic mutation SARS-CoV-2, especially the Oxford-AstraZeneca vaccine, cannot defend against the so-called “South African” variant.
The reality is that the three available vaccines already provide data in this regard, and these data are also incomparable. MRNA vaccines only show laboratory studies, in which the defensive capabilities of their vaccines have been disturbed to a certain extent, especially for MRNA vaccines. South African variant.
Taking Oxford-AstraZeneca as an example, they went further and conducted a small clinical trial in South Africa. They observed that the vaccine could not prevent the mild to moderate form of the disease caused by the South African variant. This does not mean that the vaccine will not continue to protect against serious diseases, which can lead to hospitalization and death.
If we develop vaccines in less than a year, it should take less time to adapt them to new variants
And we don’t know how the mRNA vaccine behaves in clinical trials using the same variant.In any case, the overall must be assured, because even though the variant has learned Defensive response to avoid vaccinesIn the “all or nothing” plan, this will not happen suddenly, but it will be a gradual process, and we will monitor it from day one. If we can develop a vaccine in less than a year and adapt and update it when necessary to adapt to the new genetic variation of the virus, the time required will be greatly reduced.
The three vaccines available in Spain against covid-19 differ in terms of vaccine type, vaccination schedule and approved age of use, but they all have the same thing in common Good safety and excellent efficacyThis has been confirmed from the data accumulated in its large-scale applications around the world.
Don’t forget that the minimum efficacy set by the World Health Organization is 50%, which is a goal far exceeded by the three vaccines. In fact, when we talk about what is really important: avoiding serious forms of covid, the efficacy is close 100%. -19, those who were hospitalized and died conditionally.
Federico Martinón-Torres He is the Director of the Pediatrics Department of the University Hospital of Siriago in Santiago, the coordinator of the WHO Santiago de Compostela Vaccine Safety Cooperation Center, and a member of the WHO European Vaccine Advisory Committee.