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The development of Covid-19 vaccines is progressing at an unprecedented speed. Vaccines that were mere blueprints in January when the coronavirus began spreading globally already have advanced into massive Phase 3 clinical trials. The U.S. government wants hundreds of millions of doses of Covid-19 vaccine or multiple vaccines ready to distribute by January.

Many experts have raised concerns about this highly compressed development schedule. But this week, Steven Salzberg, a Johns Hopkins University professor and biomedical engineer, took the opposite tack. Writing in Forbes, Salzberg said that we should be reasonably confident already about the safety and efficacy of experimental Covid-19 vaccines and that we should start inoculating millions of Americans today.


So his out-of-the box vaccination idea was greeted with a fair amount of pushback, including an op-ed in the New York Times and what seemed like thousands of critical comments on Twitter. And so one day later, Salzberg backtracked, admitting that his vaccination idea was maybe wrong. He called in to STAT’s podcast, “The Readout LOUD,” to discuss the controversy that ensued.

This transcript has been lightly edited for clarity.

Steven, how are you feeling? It’s been a little bit of a rough and tumble week for you, especially on Twitter.


Yes, it was quite overwhelming on Sunday and on Monday. I’m not used to getting that kind of pushback.

Take us back to the intent of your original idea. What were you trying to advocate and why?

Well, it started with the there’s a personal aspect; I would like to get vaccinated myself. I’m a professor at Hopkins, and we’re bringing students back in just a few weeks and we are supposedly going to be testing everybody, but there isn’t a concrete plan in place. A lot of the faculty are naturally concerned about being exposed to the virus, and we’re all waiting for the vaccine.

I’ve been following the Phase 1, Phase 2 trials of several different vaccines very closely. And it occurred to me, and I’m sure many other people, that once once you start Phase 3, as several manufacturers have started, you know, you’re giving the vaccine to tens of thousands of people. So clearly, the people who developed it have decided that the vaccines are pretty safe. Otherwise, you couldn’t possibly give them to 30,000 people like they’re doing. But the frustrating part is that, first, that I can’t get it. And people said you should just sign up. But you can’t just sign up. They’re overwhelmed by volunteers. So they’ve already got everybody signed up they want. And, also, I’m not a good candidate for the vaccine trials. They’re giving it to a lot of people, but they want people who are at high risk for getting the virus — in other words, people whose jobs or something about their life is going to make them get exposed more likely. They run this trial where they give half the people the vaccine, half the people a placebo and then they just wait and see how many people get infected.

I’m not a good candidate because I’m working from home. So I’m not at high risk. So I’m like the rest of the world; I’m going to have to wait. So it occurred to me that, well, why? Why not just start ramping up production since it’s already safe enough to give to 30,000? Why not give it to many more people if they’re properly informed? So that was my idea. It kind of blew up.

Right. So the pushback came pretty quickly with scientists and various experts expressing concerns. I saw that Otis Brawley, a colleague of yours at Johns Hopkins, pointed to the example of the swine flu vaccine of the 1970s, which had to be pulled off the market. I mean, in hindsight, do you feel like that the logic you just described was a little too cavalier or what were the issues?

No, I don’t think the logic is cavalier. I think that I perhaps underestimated the risk. The points that people made that I thought were most compelling — people wrote to me directly and sent me papers — were that in Phase 3, because you have many more people involved, you may start to see side effects that affect a small percentage of the population that you didn’t see in the small Phase 1 and Phase 2 trials. And so we don’t know yet. … If you did see a bad side effect, even in a small percentage of people, that might be enough to say this vaccine just isn’t safe, because when you’re giving it to millions or hundreds of millions of healthy people, you know, even a small percentage of bad side effects is pretty bad.

Vaccine hesitancy is a growing problem in the U.S. I know you have done battle yourself with the anti-vaccine movement. Are you concerned at all that the ultra-fast development of Covid-19 vaccines may, you know, inadvertently dissuade Americans from being vaccinated?

Actually, I’m not really worried about that. I worry a lot about the anti-vax movement. As you noted, I’ve been blogging about the safety of vaccines and about the problems with the anti-vaccine movement for 12 years. And they continue to spread misinformation and try to stoke fear of vaccines and nothing will stop them. I’ve seen their strategies and their behavior over the years. Just telling them facts doesn’t seem to sink in.

So I think that no matter what you do to develop a Covid-19 vaccine, people in that movement will say that it’s not safe and they won’t take it. They’ve already been saying that. They were saying that as soon as word started getting out that vaccines were being developed.

I think we have to be careful about how we present the vaccines and we have to be open about all the science … but I don’t think that there’s much we can do to prevent the anti-vaxxers from saying the sort of things they’ll say.

In your follow-up blog post, you wrote, “One thing I’ve learned as a scientist is that if you get something wrong, you need to admit it. Learn from the experience and move on. I was wrong.”

That was also a very strong reaction, but it was quite the opposite from the reaction to my original piece. It’s been very positive. Many, many people commented on Twitter that they really appreciated that I acknowledged my error and they were lamenting that this isn’t more common these days —most people just double down when they get caught in a mistake. Many people wrote to me directly and said that I restored their faith in my credibility. So that was that was very rewarding to get that feedback. So I’m glad I did it.

Last question: After that whirlwind few days on the internet, do you still like being on Twitter?

That’s a very good question. I’ve been off of it mostly since a couple of days ago because it was so overwhelming. I have a full-time job. This blogging I do at Forbes is really something I do on the weekends. So it’s very distracting. I find science Twitter, which I engage in a lot, to be pretty useful as a way of sort of sharing scientific results and new papers. So I’m going to continue to do that. But the sort of other aspects of Twitter are not always so positive.

This is a lightly edited transcript from a recent episode of STAT’s biotech podcast, “The Readout LOUD.” Like it? Consider subscribing to hear every episode. 

  • It’s rather shocking that a professor at JHU is so ignorant about vaccine development, so bold to advocate for something he is clueless.

    “So clearly, the people who developed it have decided that the vaccines are pretty safe. Otherwise, you couldn’t possibly give them to 30,000 people like they’re doing.”

    He go it completely wrong. the reason for such a large population for phase 3 trial is not because it’s safe based on Phase 1/2 trials, rather, phase 3 is designed to find not only efficacy, more importantly, the safety profile. Vaccines will be used by hundreds of millions people (including people with all kinds of underlying health issues), the number 1 priority is not efficacy, it’s safety profile. Without a large phase 3 trial, it’s very difficult to identify any toxicity issues.

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