Frequently Asked Questions

No, you cannot get the flu from the flu shot or flu mist.

• The flu shot contains inactivated (killed) virus, which cannot cause infection.
• The nasal spray (flu mist) contains weakened live virus, but it's engineered so it can't cause illness in healthy individuals.

Before vaccines are approved, they go through extensive safety testing. In clinical trials where participants received either a flu vaccine or a placebo (saltwater), the only notable difference was mild soreness or redness at the injection site in those who got the flu shot. There were no increased rates of fever, cough, or flu-like symptoms.

No, vaccines do not cause autism.

Despite ongoing concerns, large-scale, well-designed studies have consistently shown no causal relationship between vaccines and autism.

• In 2004, the Institute of Medicine reviewed multiple large-scale studies and concluded there is no evidence that thimerosal-containing vaccines or the MMR (measles, mumps, rubella) vaccine cause autism.
• Since then, dozens of high-quality studies involving hundreds of thousands of children have confirmed the same results.
• In 2009, after reviewing over 900 medical studies and expert testimony, the U.S. Court of Federal Claims found the evidence to be "overwhelmingly contrary" to any link between autism and vaccines.
• Newer reviews and studies published in 2020-2025 (including a 2025 review in Trends in Pediatrics) continue to support the conclusion that vaccines (including MMR, DPT, and others) do not cause autism.

Major health organizations - including the CDC, World Health Organization, Health Canada, and the European Medicines Agency - all agree. The CDC and other health authorities remain committed to vaccine safety and are continuing to monitor and study vaccine outcomes as part of routine surveillance.