Moderna vaccine: 3 key details forecast a brighter future

On Monday, the drugmaker Moderna announced the results of a large-scale human trial evaluating the company’s coronavirus vaccine. It’s good news amid case counts hitting a record high: interim results show that the vaccine was 94.5 percent effective in preventing Covid-19.

That number puts it in league with the Pfizer vaccine, which claimed to be 90 percent effective in preventing infection. It's another signal that there is a light at the end of this pandemic tunnel.

That 94.5 effectiveness number comes from interim results of Moderna's Phase 3 clinical trial – the third and largest stage of human vaccine testing. This trial included more than 30,000 people who got the vaccine or a placebo, but these results come from a sample of 95 people who actually contracted Covid-19. Just five of those infected received the vaccine, the rest were in a placebo group.

Editor's Note: On Monday, 11/30, Moderna, Inc. announced that its vaccine efficacy against severe Covid-19 was 100 percent. The company intends to apply to the FDA for emergency use authorization.

The results were announced in a company press release. The data has not been published in a peer-reviewed journal.

Rama Rao is a professor at the Emory Vaccine Cente and was not involved with the research. He comments that this percent could change — although the change may not be by very much.

“They can certainly change as bigger numbers come in,” Rao tells Inverse. “However, I would guess the efficacy would not drop below 80 percent.”

The results arrive just as the U.S. faces a seven-day average of more than 150,000 new cases per day. The vaccine can’t replace our efforts to control the loss of life in the coming months, but it does hint that there’s an end-date for the pandemic as we’re living experiencing it now.

“The vaccine is really the light at the end of the tunnel,” said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, on a call with reporters Monday.

Moderna’s vaccine trial reveals more detailed information about:

• How a vaccine can help the most severe cases
• How a vaccine can protect the most vulnerable people

Those are two key points that will tell us how well a vaccine can control the pandemic.

Unlike the Pfizer vaccine, it can be stored for longer periods of time in normal refrigerators — a critical detail that will serve as an advantage when a vaccine is eventually distributed.

The Moderna vaccine compared to the Pfizer vaccine

Moderna’s press release includes slightly more information on demographics and severe cases than Pfizer's.

Moderna’s interim data shows that, in a sample of 95 people who got sick, 11 got severe cases of the virus. None of those 11 people were in the vaccine group.

Pfizer’s data, also released in a press release, did not mention how the vaccine performs against severe disease. This announcement from Moderna signals that the vaccine performs well against the worst coronavirus cases, suggesting that it could help declaw the pandemic's worst consequences.

Marissa Bottazzi, associate dean of the National School of Tropical Medicine at The Baylor College of Medicine and did not contribute to this research. More data needs to come in before she's too optimistic, Bottazzi tells Inverse — warning that 11 people is still a small sample.

The Moderna trial also provides a demographic breakdown of who contracted the virus. Of those 95 people who got sick, 15 were aged 65 and older. But we don't know if any of them were in the vaccine group just yet. Bottazzi points out that scientists still only have a press release to work with, so it’s hard to know how the vaccine is faring in older populations — although Tal Zaks, Moderna’s Chief Medical Officer told the BBC that the vaccine “does not appear to lose its potency” with age.

Rao does say Moderna's vaccine trials from Phase 1 and 2 suggest positive results.

“I have seen the phase ½ data in the elderly and it looks quite good,” he says.

Distributing mRNA vaccines: What comes next

The Moderna vaccine is an mRNA vaccine. It contains the genetic blueprints the body needs to manufacture a piece of the coronavirus. In this case, what's being manufactured is the spike protein. The vaccine can prompt the body to recognize that protein and fight off the real coronavirus if infected.

This is the same technology used by the Pfizer vaccine. However, the Pfizer vaccine required special coolers for transport that keep the vaccine cooled to -80 degrees celsius (-112 degrees Fahrenheit). This vaccine can be kept for about 30 days at -20 degrees celsius (-4 degrees Fahrenheit), and six months if kept at -60 degrees celsius. Rao calls that a “great advantage” for vaccine rollout.

The temperature advantage may not solve other, larger-scale rollout issues, explains Bottazzi.

“I think that the challenge will also, of course, be in how they can scale it up as a platform,” she explains.

There are no currently available mRNA vaccines on the market. Training facilities to produce new technology en masse could be the next hurdle, Bottazzi says.

Both the Pfizer and the Moderna vaccine will have to face that hurdle. Right now, Moderna has indicated that 20 million vaccines would be available by January (Pfizer has said it could produce about 50 million) – but the vaccine would require two shots. That means 10 million people could receive the full schedule.

The Pfizer and Moderna vaccine would both require two doses of the vaccine three weeks or four weeks apart. Whether we may need a booster shot a year or so later is still unclear as well. That's a "critical question" Rao adds, and one that may also affect how much vaccine needs to be produced.

What to know for the near future — This good news comes along with a "dire" situation in the US, says Bottazzi. Cases are climbing so rapidly, that we will likely know more about the vaccine's effectiveness soon as more people get sick.

But that comes at a high cost: deaths in the US have hovered around 1,000 per day in November.

The bottom line is that a vaccine still can't get us through the winter. But it can give us a hint at an end on the horizon. The critical point, says Bottazzi is to get the virus under control now, so more people reach that end date.

"The bottom line is that we really need to figure out a way to reduce the level of virus circulating in the community," she says.