Delaying The Second Dose Of Astrazeneca "has No Scientific Basis"

Delaying the second dose of AstraZeneca “has no scientific basis”

The experts respond to the decision of the Public Health Commission to space the booster injection until 16 weeks.

Image of a vial of Vaxzevria.

The precautionary principle has been the argument used by the Public Health Commission of the Ministry of Health to increase the administration interval of the second dose of the AstraZeneca vaccine from 12 to 16 weeks in those people under 60 years of age who have already received the first.

This Tuesday, May 4, those who were previously vaccinated should receive the new injection. Altogether, some 350,000 people who were inoculated in February will have to wait until June to be pricked again. They just don’t know yet if they will be with Vaxzevria, the British laboratory’s preparation, or Comirnaty, the Pfizer and BioNTech vaccine.

According to the ministry, in this way it will be possible to review the pharmacovigilance data that is published on the study of the second dose in this age group, to which the doctors and researchers reply: there is already enough information about it and everything indicates that it is safe to administer the second vaccine.

This is how he expresses it Isabella Jimeno, coordinator of the working group on vaccines of the Spanish Society of General and Family Physicians: “With the studies and reports that both the EMA (European Medicines Agency) and the FDA (United States Food and Drug Administration) have published , the second dose should be given to those who have the first“.

The doctor does not see the point in spacing out the booster dose. “There is no reason to increase the time to administer it.” In addition, it is something for which there is no positive evidence, something that the Valme Hospital researcher also recalls Antonio Gutierrez.

In a Twitter thread, he recalled that “delaying the administration of a second dose of AstraZeneca has no scientific basis.” Furthermore, recent data indicates that Increasing the ‘boost’ period can increase the spread of the virus and, therefore, mortality.

The researcher also points to the CombiVacs study, which aims to evaluate the combination with a dose of the Pfizer vaccine, but recalls that the control group (that is, against which its effect is compared) is that of a single dose. Therefore, the objective would be not to give that second dose, something that, in his opinion, is wrong.

“Support” from medical societies

The Ministry of Health affirms that the decision to postpone the second dose has the “support” of the Federation of Medical Scientific Associations of Spain, Facme, which brings together all the medical societies that have the specialty recognized in Spain.

From Facme “we have analyzed the evidence and sent a consensus report” to the Commission, he explains Cristina Avendano, which coordinates the experts on vaccines from the different societies. This report “starts from the basis that we have enough data to say that delaying the administration of this second dose does not cause any harm for these people [que ya han recibido la primera], and that we are close to having more evidence in the coming weeks.”

However, specialists have been asking for the second dose of AstraZeneca to be administered normally to people who have already received the first. Fernando Moraga-Llop, vice president of the Spanish Association of Vaccinology, already indicated to this medium that this was “the only” correct scenario. “This is what the data sheet says, it is recommended by the EMA, the WHO, the UK drug regulatory agency and many other scientific societies.”