Rate of measles cases and deaths in the United States, 1919 to 2024

I asked an AI about the drop in measles cases and mortality, and also the claim, today, that 1 in 5 children who get measles will be hospitalized – which is wild for those of us who grew up before the vaccine was available and essentially all children had measles. 1 in 5 kids then, were not hospitalized.

Why Measles Mortality Fell Before the Vaccine

The steep decline in deaths before 1963 is a well‑documented public‑health phenomenon, and it wasn’t unique to measles. Mortality from all infectious diseases fell sharply from ~1900–1960 due to broad improvements in living conditions.

1. Nutrition improved dramatically

Children in 1900 were far more likely to be malnourished. By the 1930s–1950s:

• diets improved,
• vitamin A deficiency declined,
• children were healthier overall.

Measles is far more deadly in malnourished children. Better nutrition alone slashes the case‑fatality rate.

2. Sanitation and clean water reduced background illness

Measles kills mostly through complications—especially pneumonia. When children are chronically sick from contaminated water or bacterial infections, measles becomes far more dangerous. As sanitation improved, the “stacking” of infections declined.

3. Medical care improved even before antibiotics

Supportive care got better:

• oxygen therapy,
• hydration management,
• hospital nursing,
• later, antibiotics for secondary pneumonia (a major cause of measles deaths).

These don’t prevent measles, but they prevent measles deaths.

4. Overcrowding declined

Early‑20th‑century urban housing was extremely crowded. Multiple simultaneous infections made measles far more severe. As housing improved, severity dropped.

Mortality fell long before the vaccine.

Incidence did NOT fall before the vaccine.

The chart shows this clearly: cases stayed high and cyclical until the mid‑1960s. Nearly every child still caught measles.

What changed was the risk of dying once infected.

The vaccine didn’t reduce mortality because mortality was already low—it reduced cases, which is the only way to drive deaths to essentially zero.

About the “1 in 5 hospitalized” claim

That statistic refers to modern U.S. outbreaks, not the 1950s or 1960s. And it’s not because measles has become more dangerous—it’s because:

1. Hospitalization thresholds today are much lower

In the 1950s, a child with dehydration or pneumonia might have been treated at home. Today, clinicians admit earlier and more often, especially during outbreaks.

2. Hospitalization is partly precautionary

Measles is highly contagious, and hospitals isolate cases to prevent spread. That counts as “hospitalization” even if the child isn’t critically ill.

3. The statistic comes from small, modern outbreaks

When outbreaks are small, even a handful of hospitalizations can make the percentage look large.

4. Case detection is different today

In the 1950s, mild cases were often never reported. Today, nearly every confirmed case is counted, and many are diagnosed in clinical settings where hospitalization is more likely.

So the “1 in 5” figure is not directly comparable to historical data.

By the early 1960s in the U.S.:

• mortality was already extremely low,
• most children recovered without complications,
• measles was still widespread.

Is modern messaging exaggerated?

✔ It’s true

Measles mortality had already fallen dramatically before the vaccine.

✔ It’s true

Most children in the 1950s and early 1960s recovered without hospitalization.

✔ It’s also true

Measles is still dangerous in populations with poor nutrition, low vaccination, or limited medical care. That’s why it remains deadly in parts of the world today.

✔ And it’s true

The vaccine’s biggest impact was eliminating cases, not reducing mortality.

✔ The modern “1 in 5 hospitalized” statistic is context‑dependent

It reflects modern medical practice, not a sudden increase in measles severity.