The Centers for Disease Control and Prevention’s plans to consolidate data on diseases like measles and polio are raising concerns about patient privacy, delays in spotting long-term trends and ways the Trump administration may use the information.

The agency told state officials earlier this week that it would shift disease information to a new system managed by Palantir, the data analysis and technology firm co-founded by Peter Thiel.

The change is not entirely unexpected. The Covid pandemic revealed that the C.D.C.’s data systems were antiquated, hobbling the country’s response in the crucial early months. A plan to modernize and consolidate the agency’s data systems began during the Biden administration.

But news that the Trump administration has expanded Palantir’s work across the federal government in recent months, allowing it to compile detailed information about Americans, has introduced a new layer of anxiety and mistrust among state and local officials about sharing data with the C.D.C.

Palantir’s systems, including those at the C.D.C., rely on a platform called Foundry that could merge information from different agencies. The Department of Health and Human Services, the Food and Drug Administration and the National Institutes of Health all use Foundry.

Some officials worry that a sprawling data collection system could expose or endanger people with sensitive health needs, like gender care, reproductive health care or disabilities. Some labor and other advocacy groups have tried to block the Trump administration from sharing data across agencies.