Shares of health-care companies were higher.

Food and Drug Administration officials pushed back Tuesday against claims that their decision to authorize antibody-rich convalescent blood plasma for Covid-19 patients had been politicized. The FDA "reviewed data from multiple sources, including over a dozen published studies," as well as recent data from a national expanded access study sponsored by the agency and led by the Mayo Clinic in Rochester, Minn., in making its decision, according to a statement from Peter Marks, a senior official involved in the decision.

The agency authorized convalescent plasma - derived from patients who have survived the virus - on Sunday as a potentially effective product against the new coronavirus, after President Trump criticized the FDA as delaying such an authorization.

Meanwhile, the coronavirus pandemic has put the once-niche category of telemedicine in the spotlight and is now driving a flurry of deal activity involving virtual health-care providers. Telehealth company American Well Corp., known as Amwell, on Monday filed a registration statement for an initial public offering. MDLive Inc., a rival telehealth company, is preparing for an IPO early next year, and Talkspace, a text-based therapy company, is seen by some as a target for companies interested in expanding their behavioral health platforms.

The percentage of working Americans testing positive for drugs climbed last year, particularly for marijuana, according to a new report, indicating employee drug use was on the rise just as the coronavirus pandemic created new stresses. Overall, the proportion of U.S. workers who tested positive for drugs in urine in 2019 rose to 4.5%, the highest level in 16 years, according to Quest Diagnostics Inc., one of the largest drug-testing laboratories in the U.S., which analyzed approximately nine million tests last year on behalf of employers. 


 Write to Amy Pessetto at amy.pessetto@dowjones.com