Measles is more than just a childhood illness. It’s a sneaky virus that can wipe out your immune system’s memory, making you vulnerable to diseases you thought you had already beaten.

    For a long time, measles was seen as a normal part of growing up. But it’s far from harmless. About 1 out of 20 kids who get measles end up with pneumonia, and sadly, around 3 out of 1, 000 don’t make it. Even kids who recover well from measles can face serious problems later on.

    Scientists have discovered that measles doesn’t just make you sick—it can erase parts of your immune system’s memory. This means that even if you’ve built up immunity to other diseases, like chickenpox, measles can wipe out that protection. It’s like hitting a reset button on your immune system.

    This discovery came from tracking childhood deaths. Researchers noticed that after measles outbreaks, there were spikes in deaths from other infections. This led them to think that measles was weakening immunity to other pathogens.

    To test this idea, scientists studied blood samples from unvaccinated kids before and after a measles outbreak. They found that measles had wiped out a huge chunk of the kids’ antibodies—the proteins that help fight off viruses and bacteria. This means that measles can make you almost as vulnerable to other diseases as if you had never been exposed to them before.

    The findings were shocking. To confirm, scientists turned to monkeys. They found that macaques infected with measles lost a significant amount of their existing antibodies. This suggested that measles destroys a crucial type of immune cell called long-lived plasma cells, which produce protective antibodies for decades.

    So, how does measles do this? It turns out that measles binds to immune cells, hijacking them and spreading through the bloodstream to organs like the spleen and lymph nodes. As the immune system fights back, these infected memory cells are destroyed, along with their record of past battles.

    This isn’t permanent. Survivors do gain lifelong immunity to measles itself. But after that, the immune system rebuilds—but not in the way it was before. New memory cells are created, but they’re now measles-focused and less on other, previous infections. Some researchers call this the “measles paradox. ” During this time, measles survivors face a higher risk of secondary infections.

    The good news is that vaccines can prevent this. By blocking the virus from infecting the immune system in the first place, vaccines also preserve immunity to other diseases. A single dose of vaccine is 93% effective at preventing measles, while two doses offer 97% protection.

    Yet, unfortunately, we’re seeing an increase in anti-scientific claims that lead to lower vaccination rates, and the effects are already showing. In early 2024, an outbreak in Ohio highlighted the dangers of low vaccination rates. The outbreak, which sickened dozens of children, was traced to a community with low MMR (measles, mumps, and rubella) vaccine uptake due to vaccine hesitancy. Nearly all infected individuals were unvaccinated.

    Something similar is happening in 2025 in Texas and Ontario, with the US reporting the first death attributable to measles in a decade. We’ve already seen that if vaccinations drop, things can turn south quickly.

    In 2019, a devastating measles epidemic in Samoa infected 5, 667 people—8% of the population under 15. The outbreak was fueled by plummeting vaccination rates after misinformation spread about vaccine safety. In a desperate effort to control the outbreak, the Samoan government declared a state of emergency and launched a door-to-door vaccination campaign, but not before 81 people—mostly children—lost their lives.

    Keeping measles at bay is more important than ever. Even if measles itself doesn’t seem severe, its aftershocks can be threatening. The virus erases a person’s immunological history, leaving them vulnerable in ways they never expected.

    We have an extremely efficient weapon against this problem: vaccination. Whether or not we’ll end up using it effectively remains to be seen.

Measles: The Immune System Eraser

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