Is there a link between HPV vaccines and autoimmune, rare diseases?

The association of human papillomavirus vaccination with autoimmune and other rare diseases remains unclear, results of a systematic review and meta-analysis have shown.

“The review also highlights the need for more systematic collaborations to monitor rare safety adverse events,” the investigators said.

Literature databases were searched to identify any postlicensure safety studies related to HPV vaccines and autoimmune adverse events from inception to 16 April 2019. Fixed- or random-effects models were used to compute pooled risk estimates if at least two estimates per disease and per HPV vaccine were available.

Twenty-two studies were included in the meta-analysis, all of which applied different methodologies and used various types of data sources and outcome definitions. The most commonly assessed therapy was quadrivalent HPV vaccine (4vHPV), while the most frequently reported diseases were type 1 diabetes mellitus, immune thrombocytopaenia purpura and thyroiditis.

Thirty-five diseases, corresponding to 48 pooled risk estimates, were included in the meta-analysis. No significant effect was seen in majority of the pooled estimates (n=43). Three negative (paralysis, immune thrombocytopaenia purpura and chronic fatigue syndrome) and two positive (Hashimoto and Raynaud diseases) associations were found.

“Because of the limited number of subjects in prelicensure studies, autoimmune diseases and other rare adverse effects of vaccines may go undetected,” the investigators said. “Since 2006, millions of HPV vaccine doses have been distributed and a considerable amount of postlicensure safety data has been generated.”