WASHINGTON (AP) — U.S. officials say they expect health insurance companies will cover vaccines for COVID-19 without charging copays, once those vaccines are developed and become available.

At a briefing for reporters Tuesday, a senior Trump administration official said the government has been talking with insurers about offering vaccines at no cost to patients. The industry earlier made a similar commitment to cover testing for the coronavirus without charging copays.

The White House has launched an initiative to quickly manufacture millions of doses of COVID vaccines, once the Food and Drug Administration approves one or more formulations. Candidate vaccines are in early trials, and the goal — considered ambitious — is to have 300 million doses by early next year.

Senior administration officials provided an overview of that effort on Tuesday on condition that they not be publicly identified. The White House initiative, dubbed Operation Warp Speed, is a joint project of the Department of Health and Human Services and the Pentagon, under the overall direction of HHS.

Insurers generally have a strong financial interest in covering vaccines, seeing them as a win-win. Vaccination helps the insurers' customers stay healthy, and preventing disease saves the companies money.

In the case of preventive services, it goes beyond financial incentives. Insurers are also required by the Affordable Care Act to provide coverage at no charge to patients. A range of screening tests, immunizations and birth control for women are already covered under the Obama-era law. President Donald Trump is still pressing to overturn "Obamacare" as unconstitutional.