Effects of human papillomavirus (HPV) vaccination programmes on community rates of HPV-related disease and harms from vaccination

Abstract

BACKGROUND: Human papillomavirus (HPV) vaccination has the potential to enhance prevention of cervical cancer, especially in countries where screening programmes are currently unaffordable or impractical. Rare adverse events and longer-term benefits of HPV vaccination, such as effects on cancer rates, are difficult to examine in randomised controlled trials (RCTs) and require large data from population-level studies to inform decision-making. OBJECTIVES: We aimed to assess population-level effects of HPV vaccination programmes on HPV-related disease and harms from vaccination. SEARCH METHODS: We conducted electronic searches on 11 September 2024 in CENTRAL (Cochrane Library), Ovid MEDLINE and Ovid Embase. We also searched vaccine manufacturer websites and checked reference lists from an index of HPV studies and other relevant systematic reviews. SELECTION CRITERIA: We included studies that assessed the impact of HPV vaccination on the general population. This included population-level studies comparing outcomes before and after the introduction of HPV vaccine. We also included individual-level, non-randomised comparative studies, such as cohort studies, case-control studies, cross-sectional studies and self-controlled case series. DATA COLLECTION AND ANALYSIS: We used methods recommended by Cochrane. Two review authors carried out data extraction independently using pretested data extraction forms. We assessed the risk of bias of all included effect estimates using different tools according to study design. We carried out quantitative and qualitative data synthesis separately by outcome and study design. We performed meta-analysis on studies that reported effect estimates adjusted for confounding, with a focus on those receiving HPV vaccination at or before the age of 16 years (the target age group for vaccination). We rated the certainty of the evidence with GRADE. MAIN RESULTS: = 99%). Twenty-three pre-post vaccine introduction studies reported a decrease in anogenital warts incidence following the introduction of HPV vaccine. Six studies reported no difference in anogenital warts incidence. There was only very low-certainty evidence on the effect of HPV vaccination on the incidence of adenocarcinoma in situ (three studies) and vulval cancer (five studies). No studies were identified that reported on community rates of serious adverse events following HPV vaccination. Specific adverse events Across a range of study designs, HPV vaccination was not associated with an increased risk of postural orthostatic tachycardia syndrome, chronic fatigue syndrome/myalgic encephalomyelitis, paralysis, complex regional pain syndrome, premature ovarian failure, infertility or sexual activity (all moderate-certainty evidence). There was evidence that suggests HPV vaccination was not associated with an increased risk of Guillain-Barré syndrome (low-certainty evidence). AUTHORS' CONCLUSIONS: There are now long-term outcome data from different countries and from different study designs that consistently report a reduction in the development of high-grade CIN and cervical cancer in females vaccinated against HPV in early adolescence. Data show that there is greater benefit to vaccinating younger adolescents prior to becoming sexually active. There is evidence that HPV vaccination does not increase the risk of the most common adverse events reported on social media.

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