US Measles Cases Pass 4,400 as States Say CDC Refused Faster Test

US measles cases have climbed to at least 4,410 so far in 2026, according to the Centers for Disease Control and Prevention (CDC), as health officials in four West Coast states said the agency had turned down their request to validate a faster, high-volume measles test, citing “other competing priorities”. The CDC’s latest count, published on 15 October, is nearly double the 2,289 cases recorded in all of 2025.

The dispute, reported by The Guardian on 22 October, centres on whether public health laboratories will be able to scale up testing quickly if large outbreaks spread on the West Coast.

How Bad Is the US Measles Outbreak?

According to CDC figures reported by CIDRAP, cases rose by 330, or 8%, in a single week to 4,410. There have been 42 new outbreaks this year, and 96% of confirmed cases have been in people who were unvaccinated or whose vaccination status is unknown.

• Confirmed cases in 2026: at least 4,410 (CDC, as of 15 October).
• Cases in 2025: 2,289.
• Cases in 2024: 285.
• New outbreaks in 2026: 42.
• Deaths acknowledged by CDC this year: two, although Pennsylvania has reported six measles deaths in the state.

Pennsylvania has reported 1,260 cases, and experts quoted by CIDRAP said the true number of infections there could be much higher, given the number of deaths. Ohio, Kentucky and New York have also reported significant outbreaks; New York has declared a statewide health emergency.

Why Are West Coast States Clashing With the CDC Over Testing?

The West Coast Health Alliance, which includes health officials from California, Oregon, Washington and Hawaii, wrote to CDC Director Erica Schwartz asking her to reconsider. According to the letter, California and Washington asked the CDC in May to validate a high-throughput measles test, but after two months the agency declined, citing “other competing priorities”.

Many public health labs bought high-volume machines, such as the Hologic Panther Fusion, during the Covid-19 pandemic. That platform can process up to 500 tests in eight hours, but there is currently no CDC-validated measles test for it, so labs rely on lower-volume methods. “If a large outbreak were to occur in our region, without high-throughput capacity, it would be more difficult to scale up diagnostic testing appropriately,” the officials wrote.

Emily Hilliard, a spokesperson for the Department of Health and Human Services, said the CDC was “ensuring state and local health departments have the support needed to strengthen measles detection and outbreak response” and was “prioritizing emerging technologies”. She did not say whether the CDC plans to validate such a test, The Guardian reported.

Why Does Faster Testing Matter?

“With a measles outbreak, time is really of the essence,” said Benjamin Bradley, medical director of virology at ARUP Laboratories, which has published its own high-throughput measles assay. One person with measles can infect 12 to 18 unvaccinated people, and the virus can linger in the air for up to two hours.

Faster results allow health officials to isolate patients and trace contacts sooner. The MMR vaccine can prevent infection if given within 72 hours of exposure, so speed can directly stop chains of transmission.

How Can Families Protect Themselves?

• Check that children have had both recommended doses of the MMR vaccine; adults unsure of their status can ask a doctor about a blood test or a dose.
• Before international travel, make sure everyone in the family is up to date, as measles is still common in many countries.
• If someone develops a high fever and rash after possible exposure, call ahead before visiting a clinic so staff can prevent spread.
• Follow your state or local health department for exposure alerts.

Medical bills can be a shock during an illness; our guide on how to build an emergency fund explains how to prepare.

Featured image: colourised transmission electron micrograph of a measles virus particle, by NIAID / Wikimedia Commons (microscopy by CDC), CC BY 2.0.

Sources

• The Guardian — CDC denies approval for high-volume measles test, citing ‘other priorities’ (22 October 2026).
• CIDRAP — US measles cases grow by 8% in 1 week, for a total of 4,410 (October 2026).
• CDC — Measles Cases and Outbreaks (15 October 2026).
• The Seattle Times — CDC ignored request from WA, California to validate a new measles test (22 October 2026).