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Vaccinations can provide "herd immunity" and protect many from disease, NIH says
National Institutes of Health
Parents know that kids are vulnerable to a host of infectious diseases. Research supported by NIH and others proves that the benefits of vaccines in preventing illness and death greatly outweigh the risks.
The list of childhood diseases can be overwhelming: measles, mumps, rubella, diphtheria, pertussis, polio, meningitis, influenza and rotavirus. In the era before vaccines, many children in the U.S. died or became disabled from these diseases. Many still do in countries and regions with lower vaccination rates.
With all the international travel in the world these days, it’s important to keep vaccines, or immunizations, up to date. Here’s just one example of what might happen if you don’t. By 2000, immunization had practically wiped out measles in the U.S. But a measles outbreak in 2005 was traced to one unvaccinated U.S. resident infected during a visit to Europe. The returning traveler infected American children who hadn’t been vaccinated because of safety concerns—despite study after study showing that childhood vaccines are safe and effective.
A major epidemic didn’t emerge that time. That’s because enough people in the surrounding communities had already been vaccinated against measles.
“The important concept,” says Dr. Marc Lipsitch of the Harvard School of Public Health, “is that vaccinating people protects not only them, but others in the community. If I’m protected, I can protect others.”
This type of protection is known as “community immunity” or “herd immunity.” When enough of the community is immunized against a contagious disease, most other members are protected from infection because there’s little opportunity for the disease to spread.
