Autoimmune conditions are likely not triggered by the quadrivalent human papillomavirus vaccine, according to recent study findings.
Chun Chao, PhD, and colleagues at the Kaiser Permanente Department of Research and Evaluation in Pasadena, Calif., used the electronic health records of 189,629 females aged 9 to 26 years from California who had received the quadrivalent HPV vaccine (HPV4; Gardasil, Merck) to determine whether it triggered autoimmune conditions such as lupus, rheumatoid arthritis, type 1 diabetes and multiple sclerosis. The researchers studied this link because isolated cases have been reported, but the conditions have not been confirmed in larger studies.
The researchers said, overall, there were 1,014 potential new-onset cases identified, of which 719 were eligible for case review. Between 31% and 40% were confirmed as new onset, and of those cases, there was no cluster of disease related to vaccination timing, dose sequence or age found for any autoimmune condition.
Other diseases studied included thrombocytopenia, autoimmune hemolytic anemia, juvenile rheumatoid arthritis, Hashimoto’s disease, Graves’ disease, acute disseminated encephalomyelitis, Guillain-Barré syndrome, neuromyelitis optica, optic neuritis and uveitis.
The researchers said the study’s potential limitations included that “the initial presentation of autoimmune conditions often involves general symptoms, and there is often a lag between initial symptom onset and the correct assignment of diagnosis.” However, they added that “this kind of safety information may help parents with vaccination decisions.”
The researchers said their findings “offer some assurance that among a large and generalizable female population, no safety signal for autoimmune conditions was found following HPV4 vaccination in routine clinical use.”
Disclosure: A number of researchers reported financial ties to Merck, which funded the study and produces the vaccine.