The Anti-Vaccination Movement, also known as the Anti-Vaxxer Movement, is a grassroots medical activist campaign that opposes the practice of vaccination based on fears about the adverse effects of immunization. The movement is most commonly associated with discredited claims that vaccines are linked to autism spectrum disorders.
In 1998, the medical journal The Lancet published a paper by the now-discredited and former doctor Andrew Wakefield providing support for the claim that colitis and autism disorders were linked to the measles, mumps and rubella (MMR) vaccine. The paper was subsequently discredited with a series of reports released between 2004 and 2010 by British investigative reporter Brian Deer. On September 17th, 2007, the book Louder Than Words: A Mother's Journey in Healing Autism by Jenny McCarthy was released, in which the actress describes her experiences raising a child with autism. The following day, McCarthy was interviewed on the Oprah Winfrey Show, revealing that she believed an MMR vaccine triggered her son's autism.
On April 11th, 2001, the anti-vaccination website Vaccination Liberation was launched. On June 22nd, 2007, a page for "Anti-vaccination movement" was created on the wiki site Rational Wiki. On February 2nd, 2009, the website Jenny McCarthy Body Count was launched, which lists the number of illnesses and deaths that have occurred since celebrities began speaking out against vaccinations in 2007. The website has since been renamed "Anti Vaccine Body Count."
On March 17th, 2014, Time published an article titled "4 Diseases Making a Comeback Thanks to Anti-Vaxxers," which listed measles, mumps, whooping cough and chicken pox as preventable diseases that were on the rise due to anti-vaccination efforts. On July 12th, CollegeHumor released part three of the "If Google Was a Guy" sketch comedy series, in which an personified version of the Google search engine provides search results for an anti-vaxxer (shown below).
On December 15th, artist Maki Naro published a webcomic titled "Vaccines Work: Here Are the Facts" on the blogging platform Medium. In January 2015, more than 100 people were diagnosed with the measles in 15 states in the United States, which many speculated was caused by parents refusing to vaccinate their children. In February, critics of the anti-vaccination movement began posting joke reviews on the Amazon page for the book Melanie's Marvelous Measles by Australian anti-vaxxer Stephanie Messenger. On February 4th, Redditor Thalaas submitted a post titled "How I Think Anti-vaxxers view their kids," which featured a screenshot of the character Lord Farquaad from the Shrek franchise. In the first week, the post gained over 4,100 votes (92% upvoted) on the /r/AdviceAnimals subreddit.
Jim Carrey's Twitter Rant
On June 30th, 2015, American comedian actor Jim Carrey posted a series of tweets criticizing California's newly passed bill SB277, which requires the vaccination of all school children, while accusing the Governor of being a "corporate fascist" and of "poisoning more children with mercury and aluminum."
That day, many Internet users began mocking Carrey's statements for being paranoid and ill-informed. On July 1st, Redditor whispy_farts submitted an image macro featuring the character Bones from Star Trek titled "MRW Jim Carrey went on a rant about mandatory vaccine laws," which contained the caption "Dammit, Jim! / You're an actor, not a doctor" (shown below, right). In the first three hours, the post gained over 1,900 votes and 100 comments on the /r/AdviceAnimals subreddit. Im the coming days, several news sites published articles about the Twitter rant, including CNBC, LA Times, Rolling Stone, The Washington Post and UpRoxx.
YouTube Video Demonetization
On February 20th, 2019, BuzzFeed  reported that video sharing company YouTube was promoting and recommending anti-vaccination videos to people searching for videos on whether or not they should vaccinate their children (screenshots below). BuzzFeed reports that searches for "immunization," in a session without private data, produced a video that says vaccines protect children from certain disease. However, the first "Up Next" recommendation offered an Anti-Vaccination video entitled "Mom Researches Vaccines, Discovers Vaccination Horrors and Goes Vaccine Free."
Several companies told BuzzFeed that they were unaware that their advertisements were running on such channels.
Two days later, on February 22nd, YouTube announced that they will no longer run advertisements on anti-vaccination videos. A YouTube spokesperson told BuzzFeed, "We have strict policies that govern what videos we allow ads to appear on, and videos that promote anti-vaccination content are a violation of those policies. We enforce these policies vigorously, and if we find a video that violates them, we immediately take action and remove ads."
A spokesperson for Grammarly, a spell-checking software company that advertises on YouTube, told Buzzfeed, "Upon learning of this, we immediately contacted YouTube to pull our ads from appearing not only on this channel but also to ensure related content that promulgates conspiracy theories is completely excluded. We have stringent exclusion filters in place with YouTube that we believed would exclude such channels. We’ve asked YouTube to ensure this does not happen again."
 Rolling Stone – Jim Carrey Rails Against Californias Strict Vaccination Law