Anyone who has their head screwed on correctly and has a basic grasp of science knows that vaccinations save lives - and we should absolutely all be up-to-date with our shots to protect our own health, as well as the safety of those around us.
But lately, the anti-vaxxer movement has been gaining a frightening amount of momentum, thanks to some A-list celebrities giving weight to its baseless claims.
Actress Jessica Biel, who is married to pop singer Justin Timberlake, this week joined politicians in California to oppose a new law regarding medical exemptions and vaccinations.
There are a very small number of adults and children who cannot receive vaccinations due to rare medical conditions, such as those who suffer from anaphylaxis (a severe allergic reaction) after receiving a vaccine or those with severely compromised immune systems, such as people with HIV/AIDS or some cancer and transplant patients.
However, these cases are extremely unusual and exemption from having a vaccine requires the consent of a qualified medical professional.
Now it seems there are some people who are trying to exploit this loophole - including Jessica Biel and a controversial US politician, Robert F Kennedy Jr.
The pair are lobbying against a new bill, called SB 276, which is trying to introduce more oversight and regulation into the process that allows parents to get medical exemptions from vaccines for their children.
While Jessica has never officially been outed as an anti-vaxxer, in 2015, a source told In Touch Weekly that "she feels that vaccination could cause complications."
Politician Robert F Jennedy Jr, who is leading the opposition against the new law, explained exactly why he's against it.
"The biggest problem with the bill, which is something I think Jessica is concerned with, is that a doctor who has made a determination — if he has found children in this state whose doctors have determined that they're too fragile to receive vaccinations — this bill would overrule the doctors and force them to be vaccinated anyways," he told The Daily Beast.
"She was a very effective advocate," Kennedy said of Biel.
"She was very strong and very knowledgeable. Extremely well-informed. An extremely effective advocate. She knows what she's talking about … She's upset about this issue because of its particular cruelty. She has friends who have been vaccine-injured who would be forced to leave the state."
Now in an alarming new report, an anonymous Californian political staffer who was present in the meetings between Biel and politicians says the actress revealed some concerning thoughts about vaccinations.
"Jessica said that her doctor recommended the regular vaccine schedule for her kid and she refused," the legislative staffer told Jezebel.
The staffer said that Biel implied she had "doctor shopped", or visited multiple different doctors to find one who would accept her not vaccinating her child.
"She practically admitted to doctor shopping, which [the bill] SB 276 is trying to prevent. She said she wants safe vaccines and mentioned 'corporations' a lot."
WATCH BELOW: See inside Jessica Biel and Justin Timberlake's amazing Hollywood mansion. Story continues after video.
But Biel today defended herself on Instagram and says she is not an anti vaxxer.
"I am not against vaccinations — I support children getting vaccinations and I also support families having the right to make educated medical decisions for their children alongside their physicians," she wrote.
"My concern with #SB276 is solely regarding medical exemptions. My dearest friends have a child with a medical condition that warrants an exemption from vaccinations, and should this bill pass, it would greatly affect their family's ability to care for their child in this state.
"That's why I spoke to legislators and argued against this bill. Not because I don't believe in vaccinations, but because I believe in giving doctors and the families they treat the ability to decide what's best for their patients and the ability to provide that treatment.."
All in all, this is not great publicity for Jessica Biel and we can't say it's making us want to binge more of her show The Sinner on Netflix anytime soon.