Association between Human Papilloma Virus (HPV) vaccination and risk of Multiple Sclerosis: A systematic review

INTRODUCTION: The vaccination against Humanpapilloma Virus (HPV) is an effective strategy to prevent high-risk HPV infection and subsequent cervical carcinogenesis. Although the safety profile has been ascertained, the relation with the development of central nervous system (CNS) autoimmune disorders (AD) appears still controversial. Multiple Sclerosis (MS) is the most common cause of chronic neurological impairment in young people, typically striking females. The main purpose of this review was to assess the association between HPV vaccination and MS. METHODS: The systematic review of the literature was carried out using 5 search engines: MEDLINE, SCOPUS, ISI WEB OF KNOWLEDGE, GOOGLE SCHOLAR and ClinicalTrial.gov. The web search was updated on January 2017. PRISMA checklist was adopted to address the content of the systematic review. The measures of outcome were reported as relative risk (RR) in cohort studies and odds ratio (OR) in case-control studies. RESULTS: The systematic review identified 5 observational studies, 9 reviews, and 1 randomized clinical trials (RCT) pooled analysis. The RR of MS onset detected by cohort studies ranged from 1.54 (95%CI, 0.04–8.59) to 1.37 (95%CI, 0.74–3.20). Concerning case-control studies, the OR spanned from 0.3, (95%CI 0.1–0.9) to 1.60 (95%CI = 0.79–3.25) for the group exposed to HPV vaccination. No result was significant. CONCLUSION: This review showed no significant association between HPV vaccination and MS. The low statistical power of the studies agreed with the low incidence of MS disease among general population. In order to overcome the shortcoming the research may be extended to the entire pattern of CNS ADs.