Israelis celebrated this week after a report from a local TV station said that the country’s BriLife coronavirus vaccine candidate still offered strong protection against COVID-19 even after six months. But The Jerusalem Post learned that “there is no data to support this statement.”
On Saturday night, N12 reported that some 230 people who had received the highest dose of the Israeli vaccine, developed by the Israel Institute for Biological Research in Ness Ziona, were notified that they did not need a third dose of the vaccine.
“It follows that apparently after half a year, the vaccine’s effectiveness is still high, in contrast to Pfizer’s vaccine,” N12 wrote.
The report sparked a press release by NRx Pharmaceuticals, the biopharmaceutical company that signed an agreement in July to help fast-track the country’s candidate.
The agreement gives NRx exclusive worldwide development, manufacturing and marketing rights. It already announced the launch of a Phase IIb trial in Georgia earlier this month.
“These reports, based on medical determinations made at local level suggest potential performance of the BriLife vaccine at a time when ICUs around the world are racing to capacity,” said NRx CEO and Chairman Prof. Jonathan Javitt in the release that was published on Monday. “With this new information, and more expected in the coming weeks, we are preparing to submit a phase 2b/3 protocol for BriLife against an established active comparator.”
The company later responded to the Post that it has "put a spotlight on various publications regarding the effectiveness of the vaccine according to the Israeli media. The publications, as far as we understand, rely on medical details given by various individuals of their choice."
But a source who is closely involved in the Israeli trials said it is “unclear that this is really the case” and that there was “no data to support this statement.”
He said that Israel is quickly approaching the recruitment of the last couple of patients in its Phase II trial, which has been grossly prolonged first due to bureaucracy, then due to issues with dosing and finally due to the high level of vaccination in the country. The source said that the team only has preliminary data and that it cannot really comment on whether or not the rate of decline of the immunologic response is slower as compared to Pfizer.
In fact, he said that while it is true that those participants who received the high dose of the vaccine have not been asked to get a third shot, “if more than five months have lapsed since getting BriLife, then our recommendation would be to go and get a Pfizer shot. It is a risk-benefit issue.
“We don’t see the risk in getting another vaccine and the benefit is there because of the rate of the disease right now in Israel.”
Until April, the clinical trial had been testing three doses of the vaccine – low, medium and high doses. However, in a previous interview, Prof. Yossi Caraco, head of the Clinical Pharmacology Unit at Hadassah-University Medical Center, told the Post that “the low dose does not induce sufficient response. While all subjects enrolled in the low dose [arm of the trial] are still being followed up, they all have been encouraged to get a vaccination from the commercial vaccine available to all Israeli citizens.”
The participants who received the medium dose were also later encouraged to get the Pfizer vaccine.
Doctors were forced to eliminate around 200 study participants who received a low dose from the study, leaving them with only around 500 volunteers of the close to 1,000 who were supposed to be included in Phase II. Another 200 people then had to be recruited for the replacement arm, a “higher-than-high dose,” Caraco explained, “that we believe might even be better."
Since April, this is the dose they have been testing.
“We have noted that there is a correlation between the dose of the vaccine and the extent of the immunological response,” he said. “Even though we were quite satisfied with some of the doses, we do expect the higher dose may improve the results we are seeing up until now.”
The source told the Post that the team is gathering more and more data and “it seems very promising.”
BriLife is a vector-based vaccine. The vaccine takes the vesicular stomatitis virus (VSV) and genetically engineers it so that it will express the spike protein of the novel coronavirus on its envelope.
Once injected, it does not cause a disease by itself. VSV does not infect humans; instead, the body recognizes the spike protein that is expressed on the envelope and begins to develop an immunological response. The vaccine will initially be delivered by traditional injection.
“The BriLife vaccine differs from other COVID-19 vaccines by presenting the entire COVID-19 spike protein to the body’s immune system,” explained the NRx release. “It also differs from other COVID-19 vaccine approaches in that it is a self-propagating, live-virus vaccine in which the spike protein of the vaccine appears to evolve in a manner consistent with the evolution of the SARS-CoV-2 virus in nature.
“Thus, while variants may arise that support manual enrichment of the vaccine against those specific variants, the vaccine itself may continue to evolve in a manner that provides ongoing protection against variants.”
However, until the data is final, as another source close to the efforts told the Post, “I can’t and don’t want to comment on that.”