President Joe Biden has pledged to distribute 500 million rapid COVID tests to Americans, but they won’t come anywhere near fast enough to provide assurances for holiday gatherings, which are happening as the highly transmissible omicron variant spreads.

Tests have been increasingly tough to get in many areas as they have been during much of the pandemic, and the U.S. hasn’t really had a comprehensive strategy for testing. That partly reflects the priorities and structure of the U.S. health care system.

Earlier this week, professor Carri Chan, director of Columbia Business School’s health care and pharmaceutical management program, was in a common situation these days — waiting in line for a COVID-19 test.

“Demand is enormous,” she said. “There are lines around the corner.”

Chan was getting a polymerase chain reaction, or PCR test, and planned to also take rapid antigen tests at home ahead of a visit from family.

She said both have their merits and challenges: PCRs are more sensitive to smaller levels of the virus and can often be obtained for free through public programs or health care providers. But they’re slow and inconvenient, unlike home rapid antigen tests, which generally only turn positive when someone has high levels of the virus and are likely to be infectious.

“If you’re able to use these less-sensitive tests but use them very regularly, I think they can be a very important tool,” Chan said.

Using rapid tests regularly has proven to be a challenge in the U.S., where they’re harder to get and pricier than in other countries, like the U.K. or Germany.

“We haven’t authorized a sufficient number of tests to actually have the scale we need,” said Michael Mina, an epidemiologist and immunologist, formerly of Harvard, who now works with digital health platform eMed. He said the approval process has been slow and doesn’t measure benefits at a population level, “where the primary benefit of the test is not for the test user, but for the people around the test user.”

In Europe, where regulations have been less strenuous, there are nearly 40 companies manufacturing rapid tests. In the U.S., only about a dozen companies are approved.

The differences run deeper than just regulation, said Zoe McLaren, a health economist at the University of Maryland, Baltimore County. “We’re at a disadvantage in the U.S. because we have a decentralized and fragmented health care system.”

Unlike countries with national health care systems, the U.S. doesn’t have as much infrastructure to distribute tests on a mass scale. McLaren said our health system is more geared to treating diseases than preventing them. There’s more investment in drugs and procedures, less in primary care and public health.

“There are workarounds, we can work with a system that we have,” she said. “All we need to do is take the playbook for vaccines and apply it to rapid tests.”

With the help of massive government investment, private companies were able to develop and distribute vaccines in record time. McLaren said the government sending out 500 million rapid tests is a step in the right direction.