Health-care companies fell amid doubts about the sustainability of the recent recovery in the sector.

The health-care sector of the Standard & Poor's 500 is close to breakeven for the year after vaccine and coronavirus treatment developers such as Moderna and Gilead Sciences led a resurgence in share prices in recent weeks.

The three authors of a controversial study on hydroxychloroquine in Covid-19 treatment that suggested safety issues and no benefit have retracted their work, originally published in medical journal the Lancet, The Wall Street Journal reported.

San Francisco-based Verge, which is developing an experimental treatment for amyotrophic lateral sclerosis, also known as ALS, is talking to pharmaceutical companies about develop a coronavirus drug.

The Bill and Melinda Gates Foundation is pledging $1.6 billion to a global organization that provides vaccines to children in the poorest countries, with $100 million of the donation earmarked for Covid-19 vaccines, when safe and effective ones have been found.


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