Half a dose of AstraZeneca vaccine more effective than a full dose

In order to diversify sources of supply, Morocco had placed an order with the Anglo-Swedish laboratory AstraZeneca, which collaborates with the University of Oxford in Great Britain. But the effectiveness of AstraZeneca’s vaccine candidate, estimated at 70%, has recently been questioned. And it might not be worse. Because in addition to standing out by its results considered to be encouraging, it would seem that a half-dose would be more effective than a full dose for which it was originally designed to guarantee optimal protection. The researchers were surprised to find that with half the dose, the observed efficacy would be 90%, compared to only 62% protection after the injection of the second half, a month later. Decidedly, this new coronavirus will never cease to surprise us and to intrigue scientists who have obviously been quick to publicly display their incomprehension.

To put an end to the controversy, AstraZeneca researchers have assured that “a detailed investigation will be carried out to understand exactly why we obtain better efficiency with half a dose”. Then, it was Pascal Soriot, CEO of the Swedish-British pharmaceutical group, to declare: “Now that we have found what appears to be better efficacy, we need to validate it, so we need to do an additional study because we know that the efficiency is high, so we need a smaller number of patients ”.

The results of this new international study, which should therefore be rapid, will reveal whether it was a human error or a biological phenomenon. But if the effectiveness of a half-dose is confirmed, countries which are not too far advanced in the testing phases may modify the protocol so that only one half-dose is injected. Ultimately, that would be good news. Another asset in the sleeve of AstraZeneca’s vaccine against the competition. Especially since he is already one step ahead. Less expensive, it is also easier to store than the antidotes produced by Moderna or Pfizer. In addition, AstraZeneca has planned 3 billion doses, available in 2021 against 1.3 billion doses, at the end of 2021, for Pfizer and its partner BioNTech.

In a country like Morocco, where the coronavirus kills dozens of people a day, it is imperative to stop the bleeding and stop the epidemic. The vaccination campaign remains the most effective way. A path which nevertheless conceals unanswered questions and poorly lit gray areas. While the World Health Organization swears by the vaccine from the American Pfizer and the German BioNTech, whose effectiveness rate reaches 95%, Morocco has eyes only for Sinopharm and AstraZeneca to a lesser degree. Regarding the Chinese state-owned enterprise, it has reportedly developed a “safe and effective” remedy against Sars-Cov2, according to the head of government, Saad Eddine El Othmani. So much so that out of the 10 million doses ordered from the China National Biotec Group (CNBG), 1 million would already be in the hands of the government, which hopes to launch its vaccination campaign in mid-December.

That said, according to an article in the “New York Times” dated November 25, the CNBG filed less than a week ago, an application for marketing its vaccines to the Chinese Food and Drug Administration, before even to have concluded clinical trials which would normally last a year. An eagerness that has not failed to generate much criticism from the scientific community. Especially since CNBG’s publications in the context of the effectiveness of its vaccines in phase 3 trials have not yet been released. Hence certainly the lack of credibility in the eyes of the WHO. A position to which Sinopharm opposes a foolproof assurance: “Almost a million people have received the new vaccine as part of an emergency use program. So far, our advancements, whether in research and development, clinical trials, production or emergency use, dominate the world in every aspect. Only a few had mild symptoms, ”said Sinopharm Group Chairman Liu Jingzhen.

Chady Chaabi


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