US and Canada face measles milestones
Measles elimination status is a technical marker, not a clinical milestone. It depends on whether sustained transmission can be interrupted and documented with surveillance, laboratory confirmation and genetic tracing. That means a country can look โnear the lineโ even when case counts are still relatively modest, especially if testing is incomplete or outbreaks are scattered across states or provinces.
The most important signal is not a single outbreak, but the pattern behind it. When vaccine coverage drifts below the level needed to block transmission, measles can exploit small pockets of susceptibility. In practice, that means uneven uptake, exemptions and missed second doses can matter more than headline totals. The public-health question is less โhow many cases today?โ and more โhow many communities are still easy for the virus to move through?โ
There is also a systems angle. Losing elimination status does not change day-to-day care, but it can increase pressure on hospitals, public-health labs and contact-tracing teams. For families, the relevant issue is not prestige; it is the higher chance that a preventable infection becomes locally routine again, with more opportunities for severe complications in infants, immunocompromised people and others who rely on high community protection.
Because measles is so contagious, prevention depends on durability, not short-term rebound. Restoring control usually requires sustained coverage across age groups and settings, plus rapid outbreak detection. The harder part is behavioural: once confidence in routine vaccination slips, recovery can take years even if policymakers act quickly.
Losing the crown
It was a proud moment for USย health officials in 2000 when the World Health Organization declared that measles had been eliminated from the nation. The achievementย โย meaning the US had seen no continuous spread of the disease for more than 12 months โย followed a 1989 change inย recommendations that students be given a secondย dose of the measles, mumps and rubella vaccine.
Now both the US and Canada face losing this status.
The Pan American Health Organizationโs Regional Verification Commission, a body of the WHO,ย will meet Tuesdayย in Mexico City to hear dataย from each country in theย region on measles outbreaks, genetic links, vaccinations, laboratory testing and surveillance efforts from the past year.
Canada, which achievedย measles eliminationย in 1998, had an outbreakย begin last Octoberย that has reached more than 5,000 infections. Canadaย is expected to lose its status after this meeting, which would also meanย the entire Americasย region will lose its status, too.
The USโs status is also in question. The Centers for Disease Control and Prevention has reported 1,648 measles cases this year, a three-decade record.ย The US could hold onto its elimination status for a bit longer, as an outbreak in Texas was declared over in August.
But there are other outbreaks inย Utah,ย Arizona and South Carolina. Utah officials say its cluster has not been traced back to Texas through genetic testing, but aย South Carolina official said the state has not yet gotten its genetic testing results. If South Carolina cases are genetically linked to Texas, the USโs elimination designation isย at risk.
Eliminationย status is more about prestige and doesnโt change policies, said William Schaffner, a professor of medicine and infectious disease expert at the Vanderbilt University School of Medicine. Butย measlesโย gripย on the US could take years to unravel.
The nationโs infection rate is slowly ticking up and the vaccination rate continues to decline. The CDC reported less than 92.5% of kindergarteners โ below the herd immunity threshold โ got the MMRย shot for the 2024-2025 school year. And vaccination exemptions are rising.
In addition, the combination shot MMR and chickenpox vaccine is noย longer recommended for children under 4, a change made after members of anย influential vaccine panel were fired by Health and Human Services Secretary Robert F. Kennedy Jr. andย replaced with people who have expressed doubt in the Covid vaccine.
Less than 15% of kids take the MMRV vaccine, but removing access limits options and could increase costs for some patients, the American Academy of Family Physicians said in a statement.
If measles becomesย endemic again, the consequences could be far-reaching, Schaffner said. Hospitalizations and medical costs will rise in an already strained system. Complications, like measles-related pneumonia and measles encephalitis, or brain swelling in children, will become more common.
The US has alreadyย recorded threeย measles deaths this year, including in two unvaccinated Texas children. But the toll could rise sharply โย in the period before vaccines were made available, 400 to 500ย died from measles each year. โย Jessica Nix
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