"That's a good question, and the truth is, we don't know that yet", Zaks said. But they showed no major safety worries, a key first hurdle since a vaccine would be given to millions of otherwise healthy people. Moderna started working on its COVID-19 vaccine as soon as Chinese scientists put out the gene sequence for the virus in January.
"This is a different time", Offit said.
In a milestone moment in the race for a coronavirus vaccine, the first results in humans showed Moderna's vaccine candidate led to antibody responses in a handful of healthy volunteers.
The first coronavirus vaccine tested on humans appears safe and generated antibodies which stopped the virus replicating, according to early trial results shared on Monday. One participant who received the 100 microgram doses experienced redness around the injection site.
US biotech firm Moderna has reported some success in an early clinical trials for a potential coronavirus vaccine. At day 43, two weeks following the second dose, levels of binding antibodies for the 15 participants dosed at the 25 µg level were at levels seen in blood samples from people who have recovered from COVID-19.
Moderna's chief medical officer, Tal Zaks, M.D., Ph.D., said he had no T-cell data to share from the newly disclosed animal trial.
"When combined with the success in preventing viral replication in the lungs of a pre-clinical challenge model at a dose that elicited similar levels of neutralizing antibodies, these data substantiate our belief that mRNA-1273 has the potential to prevent COVID-19 disease and advance our ability to select a dose for pivotal trials", he added.
The vaccine, mRNA-1273, was also found to be generally safe and well tolerated in the early-stage study, the drug developer said. The firm's CEO Stephane Bancel said phase one is still ongoing and previewed the next steps of the trial.
Trump Removes State Department Inspector General Steve Linick
Mr Trump, in a letter to House Speaker Nancy Pelosi on Friday, said he no longer had confidence in Mr Linick's ability to serve. The State Department confirmed Linick's firing but did not comment on the reason or on whether Pompeo was under investigation.
It is being developed in a partnership with the National Institute of Allergy and Infectious Disease headed by Anthony Fauci and the clinical test was carried out by the National Institutes of Health. Phase 2 trials for the last 13 vaccines approved typically involved 361 to 7,471 subjects, and phase 3 trials can involved tens of thousands.
Based on the interim results, the phase-two study will be amended to focus on two dose levels: 50 micrograms and 100 micrograms. We're not expecting any changes to our fair value estimates for vaccine manufacturers, however, as most of the firms in our coverage with SARS-CoV-2 vaccine candidates have already stated that selling prices would be at a not-for-profit level.
President Donald Trump has said that he wants 300 million vaccine doses by January 2021 to protect the U.S. population, and his administration has provided funding to Moderna, Johnson & Johnson, and France's Sanofi.
There are more than 100 potential coronavirus vaccines in the works.
The company also said the NIH has helped test the vaccine in mice.
President Trump may have referred to the Moderna trial when he spoke briefly to reporters Sunday at the White House upon returning from Camp David.
Moderna accelerated its manufacturing capacity for mRNA-1273 and additional future products through a 10-year agreement with Lonza announced by the companies on May 1.
Moderna is expected to move the vaccine into the next stage of broader experimentation in the coming months, though the data is encouraging and the company says the vaccine could be viable for market use by the end of 2020 or early 2021.