Measles Resurgence Prompts CDC to Sequence 1,000 Virus Genomes

Genetic data could reveal if the U.S. has lost its measles elimination status, but political interference has delayed the analysis.

Apr. 5, 2026 at 10:30pm

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A highly detailed, translucent X-ray image showing the complex internal structure of a measles virus particle, conveying the scientific importance of the genetic data being analyzed to understand the resurgence of this preventable disease.Cutting-edge genetic analysis of measles virus samples could reveal if the United States has lost its hard-won elimination status for the disease.Dallas Today

The Centers for Disease Control and Prevention has sequenced the genomes of 1,000 measles viruses from outbreaks across the U.S. last year, but has been slow to publish the data that could determine if the country has lost its measles elimination status. Scientists say the data holds crucial clues about how the outbreaks started and spread, but political interference at the CDC has hampered the agency's ability to respond effectively to the resurgence of the disease.

Why it matters

Measles was declared eliminated in the U.S. in 2000 due to high vaccination rates, but declining vaccination, misinformation, and the Trump administration's budget cuts and lagging response have fueled a resurgence of the disease. Genomic data is crucial to understanding if the outbreaks represent continuous spread within the country or separate introductions from abroad, which would determine if the U.S. has lost its measles-free status.

The details

The CDC enlisted the Broad Institute to sequence the genomes of 1,000 measles virus samples from 2025 and 2026, but has been slow to publish the data. The agency has only posted 154 of the genomes online as of April 1, despite the data being ready since December. Scientists say the delay is likely due to understaffing and a learning curve, as the CDC hasn't had to sequence hundreds of measles genomes before. In contrast, the Utah Public Health Lab has rapidly shared nearly 1,000 measles genomes online since 2025, providing more timely data.

  • In December, the CDC enlisted the Broad Institute to sequence 1,000 measles virus samples from 2025 and 2026.
  • As of late March, the CDC had only posted 8 of the 1,000 genomes online.
  • By April 1, an additional 154 genomes had been posted online.

The players

Centers for Disease Control and Prevention (CDC)

The U.S. federal agency responsible for protecting public health and safety through the control and prevention of disease, injury, and disability.

Broad Institute

A leading center for virus sequencing that helped the CDC sequence 1,000 measles virus genomes.

Kristian Andersen

An evolutionary virologist at the Scripps Research Institute who is following the CDC's measles genome sequencing efforts.

Bronwyn MacInnis

The director of pathogen surveillance at the Broad Institute, who led the team that sequenced the 1,000 measles virus genomes.

Robert F. Kennedy Jr.

The Health and Human Services Secretary who has downplayed the seriousness of the measles resurgence and promoted unproven remedies.

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What they’re saying

“We should see a report in April, assuming no political interference.”

— Kristian Andersen, Evolutionary virologist, Scripps Research Institute

“I think it's incredibly important to do whole genome sequencing for outbreaks, but we shouldn't need to do this for measles in the first place, because we have an extremely effective and safe vaccine.”

— Kristian Andersen, Evolutionary virologist, Scripps Research Institute

“I applaud the science, but the more urgent need is to get measles under control as quickly as possible.”

— Rekha Lakshmanan, Executive Director, The Immunization Partnership

What’s next

The CDC is expected to complete its analysis of the 1,000 measles virus genomes before April, when the Pan American Health Organization was slated to evaluate the United States' measles elimination status. However, PAHO has delayed its evaluation until November to allow more time for the CDC's analysis.

The takeaway

The delay in publishing the crucial genomic data from the measles outbreaks highlights the political interference and understaffing issues that have hampered the CDC's ability to effectively respond to the resurgence of this preventable disease. Restoring public trust in vaccines and launching nationwide vaccination campaigns should be the top priorities to bring the measles outbreak under control.