For Israeli native and Moderna Chief Medical Officer Tal Zaks, the road to a COVID-19 vaccine came with some challenges. An unexpected one was a tense encounter with none other than Dr. Anthony Fauci last June.

“In my anxiety to get this done, the Israeli in me showed up,” Zaks quipped during a virtual conversation sponsored by the Vilna Shul April 15. “I was just bloody impatient.” Zaks recalled that he subsequently apologized to Fauci and said, “Let’s figure out how to move forward.”

That’s exactly what happened. Last November, Cambridge-based Moderna released preliminary data from its Phase 3 trial, showing that its vaccine had a more than 94 percent effectiveness rate. The FDA granted emergency-use authorization, as well as to a vaccine developed by Pfizer-BioNTech, with both using a new technology based on messenger RNA, or mRNA. Today, these vaccines continue to be used to combat the coronavirus.

“What we see in Phase 3 is bearing fruit,” Zaks said, referring to both the Moderna and Pfizer trials. “It’s holding up in real-world efficacy, swiftly making an impact.”
Zaks grew up in Israel and received a medical degree and doctorate from Ben-Gurion University. Originally trained as an oncologist, he has been working for Moderna since 2015, with previous experience at the National Institutes of Health (as a post-doc), GlaxoSmithKline, and Sanofi. Today, he lives in Newton with his wife, Meirav, who he said played a crucial role in helping him take a much-needed rest last year.

“I think it was the first phase, we were all just scrambling,” Zaks recalled. “There was no day, no night, no weekend, just a constant project. At some point, my wife said, ‘This can’t go on, honey.’” As a result, on Saturdays “I had to stop work. Not because of religion – forgive me, those [who are] better than me at that – but because I stopped working Saturday, Saturday evening. It allowed me some perspective.”

In a discussion moderated by the Vilna Shul’s Jason Weiner, Zaks shared his perspective on multiple issues, from the technology of the Moderna vaccine to its development over the past year to its ongoing rollout and the distribution in Israel, which has received 10 million doses from Moderna.

As Zaks explained, even before COVID-19, Moderna had been working with mRNA as a possible tool against infectious diseases – including in a collaboration with the FDA.

“The platform could be relevant to a pandemic,” Zaks said, adding that Moderna and the FDA “talked back and forth in October, November, December [2019] about which virus we would pick, how to get funding, etc.”

In late 2019 and early 2020, Moderna learned about a mysterious virus in Wuhan, China.

“When we started to see the pandemic first emerge, it became clear this was not a dry run but a live fire,” he said. “We all had to muster up.”
The NIH gave Moderna the go-ahead to start a vaccine trial in early January. Yet Marion Gruber, a member of the FDA team, expressed doubt that a vaccine could be ready by the end of 2020, Zaks recalled.

“Marion kind of smiled and said it was highly unlikely,” Zaks remembered. “I said I know Stéphane [Bancel, CEO of Moderna]. ‘Highly unlikely’ will not faze him.”

According to Zaks, while Gruber still expressed doubt, she said the government would work with Moderna on the initiative.

“I think there was vision and prescience on both sides of [the initiative] – Stéphane and the FDA,” Zaks said.

As Zaks explained, the Moderna vaccine uses a technique called neutralizing to prevent the novel coronavirus from infecting cells in the human body. The part of the virus that infects cells is called the spike protein. The vaccine uses mRNA technology to prime the body for the spike protein so it can generate antibodies against COVID-19.

After one shot, “You already get the production of these antibodies, some of which already have some neutralizing ability,” Zaks said. However, citing “basic immunology,” he said that Moderna added a second dose four weeks later, termed a “booster shot.”

“You get an amplified response,” Zaks said. “The level of antibodies is higher. The ability to neutralize is stronger.” And, he added, “We started talking about … a third [shot] six to 12 months later in case immunity wanes.”

Moderna first tested its vaccine in mice and other animals. Human trials then started last July, eventually including a diverse group of 30,000 Americans across 99 sites for the Phase 3 study.

“[We] looked at ZIP codes where transmission occurred across the U.S. and chose locations where the pandemic would hit the worst, [where] we could actually see cases,” Zaks said. “Minorities are adversely affected by this pandemic … We worked with national and local stakeholders important to our ability to reach out and earn the trust of people who typically do not trust government-led trials.

“I think that a sense of transparency was what enabled us to not just enroll quickly,” Zaks reflected, “but when results indicated [that the vaccine was] 94.1 percent effective, there was a belief that it was indeed true.”

He further noted the separate initiatives from Moderna and Pfizer – “two companies that, by law, cannot collude. Both used very similar technology.” And, he said, “results [from each] came in within one week. The efficacy was within 1 percent … I think it shows you the veracity of those results.”

Zaks announced in February he will leave Moderna this fall. At one point in the Vilna talk, moderator Weiner asked Zaks if his mother is the proudest in Israel.
“It’s a great source of pride,” Zaks said. “My dad did not get to see his son be this famous. But it’s a personal sense of accomplishment.”