Slowdowns in mail delivery could have serious consequences for the millions of Americans who get prescription drugs — in some cases, lifesaving treatments — through the mail.

Why it matters: Treatments for cancer, multiple sclerosis, rheumatoid arthritis and other complex diseases increasingly are sent in the mail. And the coronavirus pandemic has spurred more people to get their routine prescriptions mailed to their homes, as a safer alternative to visiting a pharmacy.

Driving the news: Postmaster General Louis DeJoy said Tuesday that he would suspend the controversial operational changes that Democrats had widely criticized as a threat to timely mail-in voting this November.

• House Speaker Nancy Pelosi said Democrats would still continue their oversight of the postal service — which has included questions for the pharmacy industry about possible delays, as well as concerns about delays for VA patients.

By the numbers: Americans received 313 million adjusted prescriptions through the mail in 2019, often for common, generic medications that treat things like high cholesterol and high blood pressure.

• Even though that's only 5% of all prescriptions, mail orders represent roughly a quarter of all drug spending, according to health data firm IQVIA, thanks to the growing mail-order business for expensive pills that treat complex diseases.

Consequently, the U.S. Postal Service has become a critical backbone of the country's medication infrastructure.

• CVS, Express Scripts and OptumRx — the three largest pharmacy benefit managers, which cover the vast majority of filled prescriptions — all use USPS to deliver drugs.
• Digital pharmacy startups like Amazon's PillPack and Honeybee Health also use USPS.

Where it stands: Even before Tuesday's announcement, the disruption to prescription deliveries seems to have been minimal.

• In the latest Axios-Ipsos Coronavirus Index, just 5% of respondents said they had been expecting a drug delivery in the past week but either hadn't gotten it or had gotten it late. (14% were expecting a delivery and got it in time.)
• But anecdotally, for the people who are experiencing delays, the worries are real.

The bottom line: "My patients who rely on their insulin, or their inhalers, or any other type of medication can't wait weeks to see whether or not their prescription will be delivered," Jacqueline Fincher, the president of the American College of Physicians, said in a statement.