THE BLOG
04/26/2016 04:34 pm ET Updated Apr 27, 2017

Talking Science: Facts About Vaccines and Herd Immunity

This week is World Immunization Week and what better way to commemorate it than by discussing the facts about vaccines and the importance of herd immunity. But first...

What exactly IS a vaccine?

A vaccine is a biological agent that stimulates a person's immune system to produce immunity to a specific pathogen, protecting the person from a disease. That's how vaccines work. You get an inactivated, attenuated, or a portion of the version of the pathogen you're hoping to avoid.

According to the CDC, routine vaccines given to children in the last two decades will prevent hundreds of millions illnesses, tens of millions hospitalizations, and prevent over 700,000 deaths. And that's just in the U.S.

Vaccinations became routine in the late 18th century, when Edward Jenner administered cowpox, which minimally affects humans, to an 8 year-old boy, so he could acquire immunity to the closely related smallpox virus, which is oftentimes deadly. After the success of the first vaccine, doctors sought to find immunizations for a multitude of common -- and deadly -- illnesses. V

accines have been created for measles, typhoid, polio, mumps, cholera, influenza, HPV, meningitis, and smallpox just to name a few.

What is "Herd Immunity"?

Another important aspect of immunization is herd immunity. According to the NIH, herd or community immunity occurs "When a critical portion of a community is immunized against a contagious disease, most members of the community are protected against that disease because there is little opportunity for an outbreak. Even those who are not eligible for certain vaccines -- such as infants, pregnant women, or immunocompromised individuals -- get some protection because the spread of contagious disease is contained."

So, choosing to get vaccinated is not only protecting yourself, but also increasing herd immunity, and as a result protecting those who are vulnerable to disease transmission.

A Troubling Trend

Despite the effectiveness of vaccines and the importance of herd immunity, there has been a growing trend of parents choosing to forgo or delay vaccinations for their children. And while it is great that parents are taking the initiative and doing research about the health of their children, one must ask, where are they getting their facts? The choice to not vaccinate is largely based on non peer-reviewed anecdotal evidence and pseudoscience, including the fraudulent 1998 study published by a British doctor that claimed vaccines caused autism. Dr. Andrew Wakefield later admitted he falsified results and lost his medical license. However, by the time the truth was revealed, the damage was already done.

Vaccination rates have dropped substantially causing herd immunity to dip below healthy "safety thresholds." Since that study was released it has had a rippling effect throughout Europe and the United States where once eradicated diseases are now back and wreaking havoc on our herd's weakest members -- infants, those in the 2 percent who might not gain immunity from a vaccination, and those with a compromised immune system (who, subsequently, cannot be vaccinated).

In 2014, Disneyland was hit with a measles outbreak that left over 90 people infected with the disease. Last June, a 6-year old boy in Spain was the first patient in 28 years to contract the bacterial infection Diphtheria. Because of the 95 percent vaccination rate in Spain, officials needed to fly the antitoxin in from Moscow to treat the sick boy. Unfortunately, it was too late and the child died from the infection.

In California, a growing number of parents in affluent neighborhoods are choosing not to vaccinate their children. As a result, some pediatricians have even taken the stance to only see patients whose parents choose to have their child vaccinated by the age of five.

In the Westside of Los Angeles, some schools have 60-70 percent parents signing PBEs, or personal belief exemptions, so they don't have to vaccinate their kids. Those rates are so high they rival non-vaccination rates in South Sudan where they are embroiled in a civil war.

California's New Law

However, these high PBE rates will change dramatically starting July 1, 2016. Last summer, California Governor, Jerry Brown signed SB 277, a bill that states every child must be vaccinated to attend a public or private school. If parents choose not to vaccinate their children for nonmedical reasons, they must home school them. This measure should slow or stop the spread of preventable diseases in California.

To learn more about the success of vaccines, here is a video about the legacy of the poliovirus vaccine.

Polio Legacy from Saleena Subaiya on Vimeo.