An infectologist has evaluated the efficacy of vaccines: in one aspect, Astra Zeneca

Arvydas Ambrozaitis, professor and infectologist at Vilnius University Medical Faculty, told the “Delfi Tema” program that the summary of product characteristics should be taken into account when solving these problems.

“It just came to our knowledge then. That interval may be shorter or longer than, for example, Astra Zeneca vaccines, 4 to 12 weeks, but Lithuania has chosen a 12-week period. And why did you choose that? an interval of 12 weeks is a better immune response (more antibodies are formed, they are formed more frequently) ”, said A. Ambrozaitis.

According to the professor, there are even fewer questions about another type of vaccine.

“For the Pfizer / BioNTech vaccine, the summary of product characteristics is very clear: three weeks. There is an opinion that something should not be adjusted unless there is a very important reason,” said A. Ambrozaitis.

The program interlocutor pointed out that the results of the clinical trials included data on volunteers who had this interval extended to six weeks.

“It just came to our attention then. However, we don’t have data for eight or twelve weeks. I think there are no obstacles, for scientific or medical reasons, to extend the interval to six weeks, but no more.

But there are both legal and regulatory issues. Drug Enforcement Services are also very important as they oversee all of these legal matters. Suppose that if some unexpected side reaction occurs or immunity does not develop, then our people are literate and might even claim that the vaccination was not done according to the manufacturers’ recommendations. The lawyers would then search according to the letter of the law, “said A. Ambrozaitis.

The scientist said that in this place “the stick has two ends”, the choice is political.

Astra Zeneca can safely wait for the second dose after vaccination.

Responding to the arguments made by the Mayor of Vilnius, Remigijus Šimašius, that for some people the long interval between two doses reduces the motivation to choose the Astra Zeneca vaccine, the professor explained that after the first dose of this vaccine, good protection is created.

“Data from clinical trials shows that 80 percent. People who receive their first dose of Astra Zeneca develop immunity as early as four weeks later. It is strong, protects against heavy forms. However, it is short-lived, for what a second dose is needed. I think people can safely wait twelve weeks. Then there will be better immunity. It would be possible to inject the second dose earlier, but then the immune response may be weaker, “explained A. Ambrozaitis.

At the same time, the professor reassured people who feared the risk of clots. According to the scientist, it is necessary to fear clots not from the vaccine, but from the disease.

“There is no proven causal link between the use of Astra Zeneca and the formation of clots. According to statistics, no clots form in the vaccine in more than one or two cases per million vaccinated people. This is almost the same frequency as in the unvaccinated population.

We do not have a scientific basis to explain how this adenovirus vaccine, the format of which has been known for many years, can cause clotting. After all, increased clotting is caused by the disease itself. More than ten percent of patients experience complications precisely due to clot formation, and even after recovery, there is an effect of those earlier clots. It is not the vaccine that you have to fear, but the disease that actually causes the clots, ”said A. Ambrozaitis.

The professor noted that in Lithuania about 12 thousand. people with various thromboembolic diseases.

“A thousand die every year from thrombosis, which has nothing to do with the vaccine. And here we still don’t have any evidence that the clot that appeared after the vaccine injection was related to the vaccine, ”said A. Ambrozaitis.

SAM: The question is not closed

The Chancellor of the Ministry of Health, Jurgita Grebenkovienė, said that the question of the interval between the two doses of the vaccine is not closed.

“So far, we see that there is still no reason to make this decision. In May and June, we will receive a series of doses of the vaccine, the majority of which will be the Comirnaty (Pfizer / BioNTech) vaccine, which is the most popular. among our population.

In the case of a deteriorating situation, such a situation that the supply of vaccines begins to stagnate, it may happen that we have to return to this issue and make those difficult decisions, taking into account both legal and administrative, financial, reputational. and other issues, ”said J. Grebenkovienė.

The Chancellor of the Ministry agreed that, mathematically, extending the time interval between two doses would have vaccinated a larger part of the population.

“It is estimated that it could go up to 13 percent. More than with the standard interval of three weeks (referring to the Pfizer – Delphi vaccine). However, the calculations and evaluations are based on the fact that we will have exactly the same popularity for this vaccine that we have now, when we have 100% consent to be vaccinated with this vaccine, ”said J. Grebenkovienė.

At that time, the Vaxzevria (Astra Zeneca) vaccine, according to the SAM Chancellor, is one aspect of why it is not attractive and is long overdue.

“The popularity of the vaccine should be expected to decrease if, for example, a decision is made to extend the interval between doses of the vaccine. It is basically the summer period. We are aware that the EU is preparing for a certificate eco-friendly digital, which will pave the way for easy travel.

Everyone also knows that the European certificate only recognizes the complete vaccinated schedule, that is, two doses. There are a lot of things that will have a good answer. We cannot (…) vaccinate much more unequivocally, ”said J. Grebenkovienė.