Moderna's coronavirus vaccine shows initial immune response

Healthy patients who received the first doses of Moderna's coronavirus vaccine appeared to have generated antibody responses to the virus, according to early phase one trial data released by the company Monday.

The big picture: This is an early snapshot of a small sample size within a trial that is focused on the vaccine's safety. This is a positive first step, but still a first step.

Details: Eight healthy volunteers who received Moderna's vaccine developed antibodies that were similar to or exceeded the level of antibodies in patients who recovered from the disease caused by the virus, depending on the size of the dose.

• Importantly, the vaccine appears to be "generally safe and well-tolerated" with no life-threatening side effects, the company said.

Yes, but: The data is limited, and there's no data yet on people older than 55 — a group that is at the highest risk of getting infected.

The stock market saw its biggest jump in weeks amid the news, with the S&P 500 rising 2.7% and the Dow Jones Industrial Average gaining more than 3% (or 700+ points), Axios' Courtenay Brown reports.

What to watch: A phase two trial has already been approved to start soon, and Moderna now expects the phase three trial for this vaccine, the most rigorously tested study, will begin by July.

• The National Institutes of Health is leading this initial trial, and taxpayers have invested a half-billion dollars in the later-stage trials.