Interview with Cristina Méndez, Head of Vaccines at Pfizer in Spain: “We are prepared in the event that a variant becomes resistant to the vaccine”

Interview with Pfizer’s Head of Vaccines: “The mRNA technology allows the genetic sequence of the S protein to be altered in order to adapt it to new variants of the virus”

Regarding the third dose: “We have not observed changes in the levels of neutralizing antibodies that allow us to predict a significant reduction in protection with two doses”

“Pfizer is aware of cases of myocarditis and pericarditis, predominantly in male adolescents and young adults – an extremely rare side effect”

It was the first covid vaccine that saw the light and, to this day, it is the most inoculated in the USA and in most of the EU countries. There are 400 million people vaccinated with it worldwide. We talk about the Pfizer-BioNtech vaccine, developed with new mRNA technology.

In its great little story of fighting the SARS-CoV-2 coronavirus, it has more lights than shadows. About one and the other we ask him, in this interview with Cristina Méndez, Pfizer Vaccines Medical Director for Southern Europe, who answers us by email. With her we talked, among other things, about the delta variant, about other variants that may arrive, the possibility of a third dose or the rare cases of myocarditis that have been detected after his vaccination.

Question: How does the Pfizer vaccine protect us against the delta variant, which is growing strong in the world?

Answer: We are studying the efficacy of our vaccine against COVID-19 as new variants become known. In our investigations, we have not found any signs that currently circulating strains evade the protection provided by our vaccine against symptomatic or severe forms of COVID19. Still, we are taking steps to be prepared should a variant become resistant to the vaccine.

In our laboratories we use pseudoviruses that include mutations of the circulating variants to evaluate, through in vitro studies, whether the neutralizing antibodies induced in vaccinated people protect against each of these emerging variants.

A: The technology of our vaccine, based on messenger RNA, would allow us to alter the genetic sequence of the S protein to be able to adapt it to new variants of the virus and to be administered as a new vaccine or as a booster dose in previously vaccinated people. In this case, additional studies will be necessary to evaluate the safety and immune response of any modified vaccine. We are in contact with regulatory agencies, as any modified vaccine or booster would be subject to regulatory approval or clearance.

P: Is it likely that you will have to get that third dose, as advertised at the time?

A: A few weeks ago we reported the persistence of protection up to six months after vaccination of the subjects included in our clinical trials. We do not know if vaccine efficacy erodes significantly over time and if it does, when a booster dose should be administered. However, if the efficacy decreases over time, it may be due to the fact that the immune response is decreasing or to the emergence of a new variant against which the current vaccine offers less protection. In the first case, that booster dose would be with the current vaccine and in the second, it is possible that a new vaccine developed from this new strain will have to be used.

In February of this year, we announced the start of a study to evaluate the safety and immunogenicity of a third dose (booster dose) of our vaccine. Based on in vitro studies to date and observations from real-world tests, we have not observed changes in neutralizing antibody levels to predict a significant reduction in protection provided by two doses of BNT162b2, but it is important Gather clinical evidence to prepare in case an additional dose or an updated vaccine is needed.

A: As previously reported and published in The New England Journal of Medicine, the final efficacy analysis of our phase III study demonstrated a 95% vaccine efficacy rate in participants with and without prior SARS-CoV-2 infection. , measured from 7 days after the second dose. Regarding cellular immunity, it is also decisive, although we are still investigating its specific roles.

Q: Until now, the data on vaccinated people in the real world have been confirming that protection that was seen in the trials, with very similar figures. Is it the usual? Is it what you expected?

A: It is very difficult to predict any situation since March 2020. The news of the approval of the vaccine was a very positive result, although I would like to emphasize that the phase III studies of the vaccines against COVID-19 are among the large clinical trials in history, based on the rigor and speed of scientific advances.

As mentioned, the data obtained globally after the start of mass vaccination campaigns confirm what was observed in clinical trials. In Israel, for example, it was shown that subjects who had received two doses of the Pfizer-BioNTech COVID-19 vaccine showed 94% protection against symptomatic clinical forms and 92% against severe, critical or fatal illness.

A: Pfizer is aware of cases of myocarditis and pericarditis, predominantly in male adolescents and young adults, after vaccination with mRNA vaccines. According to US regulatory authorities, this is an extremely rare side effect, and only an extremely small number of people experience it after vaccination. Patients usually improve rapidly, and many of them do not require treatment. It is important to note that health authorities continue to strongly recommend vaccination against COVID-19 for eligible individuals 12 years of age and older. With more than 400 million people vaccinated so far with the Pfizer-BioNTech COVID-19 vaccine, the benefit and risk profile of our vaccine remains positive.

A: From the beginning of our vaccine development program together with BioNTech, we have been committed to working towards equitable and affordable access to COVID-19 vaccines for people around the world. That is why we made an agreement with BioNTech with COVAX to supply up to 40 million doses of our vaccine against COVID-19. These doses will be supplied throughout this year at a non-profit price.

Q: Do you think it is possible to achieve herd immunity globally, despite the delay in vaccination in Africa and Asia?

A: From day one of our vaccine development program, we have sought to make our reach broad and inclusive. We have reached out to all the governments of the countries where Pfizer has a presence and to the global healthcare organizations in parallel. We are currently in talks with more than 125 countries and supranational organizations about the supply of our COVID-19 vaccine.

Thanks to this coordination work, our vaccines have reached more than 100 countries and territories in all regions of the world. In addition, we have supply agreements to supply more than 120 countries and territories and we are in advanced negotiations with many more, including the COVAX agreement that we mentioned above.

On the other hand, and thanks to the efforts of Pfizer scientists, engineers, professionals and a large investment, we have confirmed the supply of 2.5 billion doses in 2021. Our goal is to produce 3 billion doses this year and we will continue to invest and improve the processes to enable increased capacity in 2022.

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