and certain head and neck cancers, such as throat and back of mouth cancers, and genital warts. gardasil 9 doesn't protect everyone and doesn't treat cancer or hpv infection. these diseases may have many causes. your doctor may recommend screening for certain hpv-related cancers. routine cervical cancer screenings are still needed. you shouldn't get gardasil 9 if you're allergic to the vaccine, its ingredients, or yeast. tell your doctor if you have a weakened immune system, are pregnant, or plan to be. the most common side effects include injection site reactions, headache, fever, nausea, dizziness, tiredness, diarrhea, abdominal pain, and sore throat. fainting can also happen. help protect yourself against certain hpv-related cancers. talk to a doctor or pharmacist today.