Health-care companies rose as data underscored the critical importance of vaccines for fighting the pandemic.

Covid-19 vaccines from Moderna and from Pfizer and partner BioNTech are highly effective in preventing infections in real-world conditions, Centers for Disease Control officials said, providing further evidence that vaccinations can slow the spread of the virus.

Separately, the CDC issued a warning about risks of another infection wave in the U.S. The U.S. reported 86,947 on Wednesday and 77,339 on Friday last week, well above the recent nadir around 50,000 and reversing a downward trend that had lasted since March 2.

Meanwhile, a pair of experimental Covid-19 treatments produced positive results in clinical trials, the companies developing the drugs said.

Humanigen said hospitalized patients receiving its drug lenzilumab had a 54% greater likelihood of surviving without the need for mechanical ventilation with a breathing tube after one month than a control group in a late-stage trial.

Separately, a mid stage trial on healthier patients with mild to moderate symptoms showed encouraging results for a cocktail of monoclonal antibody drugs from Eli Lilly and partners GlaxoSmithKline and Vir Biotechnology.

A Canadian panel of scientists was set to recommend a halt on administering the AstraZeneca Covid-19 vaccine to people under the age of 55 in light of new research from Europe on potentially serious side effects for younger women, according to an official.

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

(END) Dow Jones Newswires

03-29-21 1705ET