Health-care companies rose amid positive vaccine developments.

Shares of Novavax surged after the drug developer said a vaccine candidate showed promise in an early-stage trial, proving safe and effective in producing antibodies in patients' blood.

Analysts at brokerage Cantor Fitzgerald said the data suggested Novavax's vaccine may be the leading candidate of several. Those sentiments weighed on the shares of rival developer, Moderna.

Johnson & Johnson said it agreed to provide 100 million doses of its Covid-19 vaccine for use in the U.S., in exchange for more than $1 billion from the federal government, implying a per-dose price of about $10. J&J previously received $456 million in U.S. funding to develop its vaccine.

Meanwhile, Moderna said it signed small-volume supply contracts with governments at prices ranging from $32 to $37 a dose, which would mean a two-dose regimen could cost as much as $74.

"When you look at it as a whole it's still forward progress," said Oliver Pursche, an independent market strategist.

"The market doesn't want to bet on Pfizer on Merck, or any single company. The market doesn't care who comes up with the vaccine, although they would be rewarded for it...the market cares that someone comes up with a cure."

Drug-store chain CVS Health said delays getting Covid-19 test results to customers are abating after backlogs led to extended wait-times that threatened to hamper efforts to contain the coronavirus pandemic.

Teva Pharmaceuticals shares rallied after the Israeli generic drug maker's second-quarter earnings surpassed Wall Street targets.

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