By Michael Erman
NEW YORK (Reuters) – A leading scientist at Pfizer Inc. said on Thursday that the company is in intense discussions with regulators to test a booster version of its coronavirus vaccine aimed specifically at a highly contagious variant that is spreading. spreading widely in South Africa and elsewhere.
A laboratory study released on Wednesday suggested that the South African virus variant may reduce the protective antibodies produced by the Pfizer / BioNTech vaccine by two-thirds, but it is unclear how much it reduces the effectiveness of the injection against this version of the pathogen. .
Phil Dormitzer, one of Pfizer’s leading viral vaccine scientists and co-author of the study, said in an interview that he believes the current vaccine is likely to still protect against the worrying variant first discovered in South Africa.
“A level of neutralizing antibodies that can be on the order of one third to half the level of neutralizing antibodies that you see against the original virus does not mean that you have only one third to half the level of protection, you may well have full protection “, he said.
University of Texas Medical Branch professor and co-author of the study, Pei-Yong Shi, said he also believes that the reduced immune response observed is likely to be significantly above where it should be to provide protection.
Shi said that in clinical trials, both the Pfizer / BioNTech vaccine and a similar injection from Moderna Inc conferred some protection after the first of two doses with an antibody response lower than the reduced levels seen in the South African variant laboratory study. .
Still, Dormitzer, scientific director of viral vaccines at Pfizer Vaccines Research and Development, said the company was developing plans to test a redesigned booster for the vaccine.
“We are not doing this mainly because we think it means that we will need to change this vaccine,” he said. “It is mainly to learn how to change the tension, both in terms of what we do at the manufacturing level and, especially, what are the clinical results.
“So if a variant appears for which there is clinical evidence of escape, we are ready to respond very quickly,” added Dormitzer.
He said the company has already made a DNA model for a vaccine prototype targeting the variant and plans to manufacture a batch of it.
The company is proposing to do a Phase I clinical trial of a booster injection of this vaccine prototype, which it would test against a booster injection of the current vaccine.
“This will be an immunogenicity study where you will look at the immune response. And these studies are much, much smaller than the gigantic studies of effectiveness,” said Dormitzer.
“In immunogenicity studies, you can observe the immune response of each person in the study. It is not as definitive as the efficacy data, for sure. But it can be obtained much more quickly,” he explained.
The company is likely to conduct some animal tests in parallel as well, he said.
The US Food and Drug Administration has not yet released a roadmap for how companies should design tests for coronavirus booster vaccines.
(Reporting by Michael Erman; Editing by Caroline Humer and Bill Berkrot)