Health-care companies rose after Moderna reported promising data on its vaccine candidate.

The biotech company said its coronavirus vaccine candidate produced a "robust" immune-system response in a significant group of people as it prepares to move to a larger, late-stage clinical trial in July.

Results published in The New England Journal of Medicine showed that a two-dose vaccination schedule induced the desired immune response in all 45 people evaluated, and was generally safe and well-tolerated, the company said.

"It certainly did what it's meant to do," said Jim Paulsen, chief investment strategist at money manager The Leuthold Group.

"There is so much money devoted to finding a vaccine, and it's being done on multiple fronts all across the globe...you've just got to believe with that much concentrated effort with significant funding behind, it's a good bet it's going to succeed."

Shares of British drugmaker AstraZeneca rallied after an anonymously sourced report from U.K. television station ITV claiming the medical journal the Lancet will publish "positive news soon" on the Covid-19 vaccine the company is developing with Oxford University.

UnitedHealth Group ticked down, but remained near record highs, after the largest health insurer by enrollees reported a sharp increase in second-quarter profit, boosted by savings from surgeries, hospital stays and doctor visits canceled amid the coronavirus pandemic. UnitedHealth also said health-care usage returned to more conventional levels toward the end of the quarter.

Write to Rob Curran at rob.curran@dowjones.com