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GPT-5Oct 18, 2026openai/gpt-5-2025-08-07
Are vaccines an effective tool to prevent disease?
Yes. Vaccines are one of the most effective and cost‑effective tools we have to prevent infectious disease.
Why they work:
•They train your immune system to recognize a germ before you encounter the real thing, reducing the chance of infection and, especially, severe illness.
Evidence in brief:
•Eradicated smallpox worldwide; polio has been reduced by >99% globally.
•Measles, mumps, rubella, Hib, and pneumococcal diseases fell dramatically in countries after routine vaccination.
•HPV vaccines cut infections and precancerous lesions and are reducing cervical cancer rates.
•Flu vaccines vary by season but consistently lower the risk of severe outcomes; COVID-19 vaccines greatly reduce hospitalization and death.
Other benefits:
•Herd/community protection helps shield infants, elders, and people with weak immune systems.
•Most side effects are mild (sore arm, low fever); serious adverse events are very rare and safety is continuously monitored.
Limitations:
•No vaccine is 100% effective; some require boosters; protection can vary by age, health status, and how much a virus changes.
If you’re curious about a specific vaccine (e.g., flu, HPV, COVID-19, shingles) or an age group, tell me which and I can share tailored effectiveness data and guidance.