Are there any significant side effects of gardasil injection?

Nothing major. No major side effects have been linked to the Gardasil vaccine. Minor side effects include headache, dizziness, nausea, vomiting, and pain at the injection site.
Not really. Gardasil is a beneficial anti-cancer vaccine. In the U.S., 3000-4000 women die each year from cervical cancer, now a vaccine-preventable disease. Gardasil is as safe as the meningitis, hepatitis, or flu shots. Some people get arm soreness, slight fever or headache, etc... Fainting after shots or blood draws happens sometimes. Very rare allergic reactions can happen with any vaccine or medication.