The deal is the latest between the US and drugmakers to secure hundreds of millions of doses of likely vaccines.
The United States’s top infectious disease scientist has hailed early trial results from Moderna’s COVID-19 vaccine as “stunningly impressive” and says the findings are an emphatic validation of experimental mRNA technology that some had doubted.
In an interview with AFP news agency on Monday, Anthony Fauci said he would have settled for injections that protected 70-75 percent of people from falling sick.
“The idea that we have a 94.5-percent effective vaccine is stunningly impressive. It is really a spectacular result that I don’t think anybody had anticipated would be this good,” he said.
Fauci leads the National Institutes of Allergies and Infectious Diseases (NIAID), which began co-developing the vaccine with the US biotech company in January, shortly after China shared the genetic sequence of the new coronavirus.
It is based on a relatively new technology that uses a synthetic version of a molecule called “messenger RNA” to hack into human cells, turning them into vaccine-making factories.
No vaccine based on this platform has ever been approved.
“There were many people who had reservations about using something that had not been tried and true over the years; in fact, some people even criticised us for that,” said Fauci.
On Monday, Moderna and NIAID announced their preliminary results based on 95 of the 30,000 volunteers they had recruited who fell ill with COVID-19.
Of the 95, 90 had been in the trial’s placebo group, and five in the group that received the drug called mRNA-1273, translating to an efficacy rate of 94.5 percent.
Fauci recalled that some had questioned whether the vaccine would prevent severe forms of COVID-19, not just mild or moderate cases – and this too had been resoundingly answered.
“There were 11 severe events, none in the vaccine group – 11 in the placebo group, so that settles the question of whether it prevents severe disease, which it definitely does.”
Moderna’s findings follow a similarly impressive result from US pharmaceutical firm Pfizer and its German partner BioNTech last week, who reported an efficacy of 90 percent for their vaccine.
On Monday, Pfizer also launched a pilot delivery programme for its experimental vaccine in four US states, as the drugmaker sought to address distribution challenges facing its ultra-cold storage requirements.
Asked whether it was too early to say if mRNA technology had now been proven, Fauci – who is usually known for his cautious statements – said the jury was definitely in.
“I think when you have two vaccines like this that have proven to be greater than 90 percent effective, I think that mRNA is here, it’s established itself, it doesn’t need to prove anything anymore.
“The data speak for themselves; it isn’t me, it isn’t my opinion – look at the data,” he said.
Traditional virus vaccines use actual viruses that have to be grown in chicken eggs or fetal cell lines and are weakened so they don’t harm people – a process that can take many months.
By contrast, the COVID-19 mRNA vaccines deliver the genetic information needed to create a protein that lies on the surface of the virus – called the spike protein – directly to cells in the human body, which then grow it.
This primes the immune system to make antibodies to the actual virus and has the major advantage of shortening vaccine development time to a matter of weeks, once scientists have the genetic sequence of the protein they want to create.
But there are still some unanswered questions, including how long the immunity lasts.
Fauci said he was “certain” it would endure to some extent, as immune system cells called “memory B cells” remained on standby to generate new antibodies to the virus.
But for how long was unclear. “We don’t know whether it’s going to be a year, two years, three years, five years, we don’t know,” he said.
The vaccine could receive emergency approval in the US within a matter of weeks.
Speaking to the New York Times DealBook online summit on Tuesday, Fauci said he was concerned about anti-vaccine sentiment in the US, the country worst hit by the pandemic.
“We have a challenge ahead of some hesitancy about getting vaccinated,” he said, adding that unless the “overwhelming majority” of Americans get vaccinated, the risk of infection will remain high.
“This is gonna be a difficult task, we’ve got to do outreach, we have to be transparent and we have to get public health issues out of the realm of political divisiveness,” Fauci said.
The US surpassed 11 million coronavirus cases on Sunday, adding one million new cases in less than a week, according to a tally by the Johns Hopkins University.