BHealthy Blog

What is Herd Immunity?

Vaccinations still remain a controversial subject, especially during back-to-school and flu seasons. However, the science has proven that vaccines help prevent the outbreak of disease within communities and save lives. But what if your being vaccinated could help save someone else’s life?

Some children and adults cannot be vaccinated for certain diseases due to allergic reactions to the vaccination, immune disorders, frailty, or being very young or elderly. These people depend on everyone around them who is vaccinated within the community to reduce the chances of a disease reaching them. This reliance on the rest of the community (the herd) is known as herd immunity. Herd immunity works by reducing the risk of a disease becoming an epidemic because most people are vaccinated and the disease cannot spread. If a large portion of the population is not vaccinated in a particular area, the likelihood of spreading highly infectious diseases greatly increases.

When Disneyland was hit with a measles outbreak in 2015, researchers realized the full effects herd immunity can play within a large group of people, and after the data was analyzed it was determined that most of those infected were not vaccinated or had not completed the sequence of vaccinations for full immunity. Of course, this is bad news when those that have intentionally chosen to not get vaccinations encounter the disease, but can be fatal for those who, for medical reasons, cannot be vaccinated.

As the number of vaccinated individuals increases, the positive effect of herd immunity increases. For some diseases, herd immunity may begin to be effective with as little as 40% of the population being vaccinated, meaning those who can’t be vaccinated (such as babies and the elderly) are less likely to contract a debilitating or fatal disease.

Since many people rely on the immunity of the majority around them for their safety from highly contagious diseases, it is highly encouraged to get vaccinated if you can.

You can stay up-to-date on vaccination schedules with your primary care physician. If you do not have one, call HealthLine at 1-888-227-8478 or search for a physician near you.