Moderna’s Covid-19 Vaccine, Explained – The New York Times

The scientists randomly assigned volunteers to get either the Moderna vaccine or a placebo. The trial was blinded, meaning that neither the volunteers nor the people running the trial knew who got what.

Over time, some of the volunteers got sick with Covid-19. To get a preliminary sense of how the trial was going, an independent board of experts took a look at the first 95 participants who got sick. Ninety of them had received the placebo, and only five had been given the vaccine. Based on that data, the board estimated that the vaccine is 94.5 percent effective.

In the short term, no. The soonest that coronavirus vaccines could possibly become widely available would be in the spring. But if effective vaccines do indeed become available — and if most people get them — the pandemic could drastically shrink. As coronavirus infections became rarer, life could gradually return to normal.

Covid-19 can lead to a mild illness, or it can lead to a severe case that requires hospitalization and oxygen support. Out of the 95 people who got sick in the Moderna study, 11 experienced severe disease. None of those 11 people were vaccinated. In other words, the five vaccinated people who got sick experienced only mild symptoms, and all of the severe cases were participants from the placebo group.

“It couldn’t be a more favorable split,” said Natalie Dean, a biostatistician at the University of Florida.

The split suggests that Moderna’s vaccine doesn’t just block the virus in most cases, but also shields the people who do get sick from the worst outcomes of the disease. It also eases concerns that a vaccine for Covid-19 may make the disease worse, not better.

Moderna recruited 30,000 volunteers across the United States to participate in its trial. A quarter of the participants are 65 years or older. White people make up 63 percent of the volunteers; 20 percent are Hispanic; 10 percent are Black; and 4 percent are Asian Americans.

The 95 people who got sick with Covid-19 reflect the diversity of Moderna’s volunteers: Fifteen were 65 or older. The group also included 12 Hispanic volunteers, four Black participants, three Asian Americans and one multiracial person. The efficacy and safety appeared the same in all of the subgroups, Moderna said in its announcement. But researchers will have to wait for the trial to advance further to confirm this finding.

[Read more on Moderna’s Covid-19 vaccine.]

Very much so….