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A 30,000-patient trial of Moderna’s coronavirus vaccine candidate, expected to start next week, has been delayed, a potential hurdle in the company’s ambitious effort to deliver key data by Thanksgiving.

Moderna is making changes to the trial plan, called a protocol, which has pushed back the expected start date of the Phase 3 study, according to investigators. The investigators, who spoke on condition of anonymity, emphasized that protocol changes are common but said it’s not clear how long the start will be delayed.

“My understanding was that they wanted to get the first vaccines given in July, and they say they’re still committed to do that,” one investigator said. “As best I can tell, they’re close to being on target for that.”


Investigators at the University of Illinois at Chicago had previously said Moderna’s trial would begin July 9. On Thursday, NIH Director Francis Collins also told lawmakers in Washington that the study would begin this month. 

Moderna did not respond to multiple emails asking about how long the delay will last, the nature of the protocol changes, or whether they have anything to do with the vaccine’s safety or manufacturing. After publication, CEO Stéphane Bancel told CNBC that Moderna still intends to start the trial in July. In a statement posted to Twitter on Thursday afternoon, the company said it has “worked closely” with the National Institutes of Health, which is funding the Phase 3 study, “to align the final protocol in order to begin the trial on time.”


The intense focus on the exact timing of the trial stems from the tight nature of the race to develop a vaccine for the novel coronavirus — and the fact that any delay could imperil Moderna’s pole position. Pfizer, working with the German firm BioNTech, plans to start a 30,000-patient study of its own later this month. AstraZeneca and Oxford University are slated to begin a similarly sized trial in August, followed by Johnson & Johnson in September.

All of the companies are working at unprecedented speed to advance their vaccines, and Moderna may not be the last to see its timeline delayed.

Developing and manufacturing vaccines at scale is always a challenging endeavor, with unexpected hitches the norm rather than the exception. Candidate vaccines that looked promising in animals can fail to deliver the same results in people. Production problems arise.

During the 2009 H1N1 flu pandemic, U.S. officials confidently predicted there would be a vaccine in the early autumn, in time to fend off an expected second wave of infections. But the new virus grew poorly in eggs, the substrate used in influenza vaccine production. By the time mass amounts of vaccines were ready for distribution, the peak of infection in the country had already passed.

Matthew Herper and Helen Branswell contributed reporting.

  • Dr Fauci said that there is a particular mutation that has occurred with the virus at the amino accid D614 & D614G that makes the virus be able to replicate better and increases viral loads. We are still trying to confirm whether people do worse because of it, but it does appear that this mutation makes it more easily transmissible.

  • There will be no vaccine for this VIRUS. “The WUHAN CHINESE VIRUS” is a common cold Virus that has been with humans since since our beginning. The reason it has not been cured, is that it is a species of virus that mutates FAST. Ever effort to cure it has failed over a long period of time. The only thing that will stop this current mutation is time and its mutation evolution!

  • Really. It takes a minimum of 2 years to reach Phase 3 Efficacy Trials. Will there be a double blind control? What kind of vaccine is it? mRNA, DNA, purified protein, vectored? Why the secrecy?

    Oh yeah. Gates and Fauci.

    • If you actually do some research instead putting on a tinfoil hat and spewing crap out of your ass, you’d know that it’s mRNA based. The FDA approved an accelerated plan for Moderna’s vaccine, hence the reason it’s already starting phase 3.

      All of these information are available publicly, including their peer-reviewed paper on the data of this vaccine. Go educate yourself.

  • I see that you are updating the webpage to save the shoddy reporting that you did in the first place. It’s too little too late now, don’t you think? Meg Tirrell writes on twitter that the CEO, Stephane Bancel, said that the protocal changes were “NOTHING MATERIAL.” In other words, damiangarde has really screwed up rushing a story to print BEFORE GETTING ALL THE FACTS. That you have to continue to update things only confirms this. I hope Stat News gets sued!!!!!!

    Meg Tirrell wrote: Moderna CEO tells me July start for #COVID19 ph3 trial is on. Wouldn’t confirm whether they’d planned a specific day (July 9 as @damiangarde
    reports). “We have always said July. And I confirm July.” Notes there are always small protocol changes to trials, but “nothing material.”

    • Why get mad? Get glad! Buy more shares on the dip. Down nearly 15% from Tuesday’s high, today’s low was a GIFT. Maybe they can concoct another negative story next week to get it back into the $20s so longs can load up.

      Rumor is MRNA’s phase 1 data is going to be announced within the next week or 2 so there isn’t much more opportunity to get in before the cat is out of the bag.

  • This vaccine, if it ever comes to be, will likely be ineffective and dangerous. We’re just being strug along. Go out and live your lives, just like they dont want you to do. Humans have survived much worse and many times over.

    • Your comment is hilarious. Yes, human beings have survived all sorts of diseases like bubonic plague, ebola, HIV, H1N1, swine flu, polio, small pox, malaria, west nile etc etc. However, how many individual humans died from those diseases? A TON. So, yes, the race will survive but many will die. I do agree that Covid has been blown completely out of proportion, however, would you knowingly go out and contract it? Even with the very tiny chance that it will be catastrophic for you personally? Yeah, me neither. So, a vaccine is important and needed and the sooner the better.

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