Quadrivalent Human Papilloma Virus Vaccine Isn't Associated with Serious Adverse Events

Concern about possible serious vaccine-related adverse events is a potential barrier to quadrivalent human papilloma virus (HPV) vaccination. To determine risk for serious adverse events after HPV vaccination, investigators analyzed patient registry data on nearly 1 million Danish and Swedish adolescent girls (age range, 10–17), of whom 300,000 received a total of 700,000 HPV vaccine (Gardasil) doses between 2006 and 2010. (Recommended HPV vaccine dosing is at 0, 2, and 6 months; hence, many girls were exposed to more than one dose.)

Fifty-three incident autoimmune, neurological, and venous thromboembolism events occurred within 180 days after HPV vaccine administration. Vaccine-exposed versus unexposed girls had small but significantly high…