There was no increased risk for development of type 1 diabetes (T1D) after vaccination for human papilloma virus (HPV), according to research published in Vaccine.
A retrospective cohort study identified all potential T1D cases from Kaiser Permanente Northern California (KPNC) members who were aged 11 to 26 years between June 2006 and December 2015. The study investigators used a sample of 100 cases to confirm diagnosis using chart reviews and also developed an algorithm to determine the onset of symptoms.
The T1D analysis population included 911,648 individuals. Of this population, 2613 individuals with T1D were identified. Of these, 388 remained after applying the algorithm and also met HPV vaccine eligibility and membership criteria. After adjusting for age, sex, race, Medicaid, and years of prior KPNC membership by stratification using a Cox multiplicative hazards model with a calendar timeline, the risk for T1D associated with HPV vaccination was compared in individuals who were vaccinated vs those who were unvaccinated during this 10-year period. The results showed no increased risk between the groups (hazard ratio, 1.21; 95% CI, 0.94-1.57).
The number of males included in the analysis was low because HPV vaccination was recommended for males starting in 2011, which is a limitation of these findings. The study investigators also noted that people who received HPV vaccine as a catch-up may have been different in unmeasured ways to those receiving the vaccine as part of a routine schedule. The same could also be true for the comparison group of unvaccinated people compared with the vaccinated group. The study population was subject to informative censoring, meaning receipt of the HPV vaccine was correlated with continued membership in KPNC and dropout rates differed for vaccinated and unvaccinated persons. There were also residual confounders that study investigators were unable to address according to the results of the sensitivity analysis.
According to the researchers, the study still “provides reassurance that during the 10-year time period after HPV vaccine was introduced, there was no substantial increased risk for [T1D] following HPV vaccination.” Further, based on the case ascertainment in this study, investigators believe it is feasible to monitor the safety of HPV vaccine with regard to T1D using automated data.
Klein NP, Goddard K, Lewis E, et al. Long term risk of developing type 1 diabetes after HPV vaccination in males and females. Vaccine. 2019;37(14):1938-1944.
This article originally appeared on Infectious Disease Advisor