A systematic review and meta-analyses of the efficacy, effectiveness, immunogenicity and safety of HPV vaccination in non-HIV immunocompromised individual

Cervical cancer is the fourth most common cancer affecting women worldwide. It is caused by persistent infection with oncogenic types of human papillomavirus (HPV). More than 200 types of HPV have been identified and more than 40 types of them infect the genital tract. HPV 16 and 18 are the two primary oncogenic types and responsible for 77% of cervical cancers (i.e. squamous cell carcinoma), and combined with HPV 31, 33, 45, 52 and 58, account for 94.9% of cervical cancers [1-3]. While HPV infections are common and usually resolve without any consequences, persistent infections with high-risk HPV can progress to premalignant glandular or squamous intraepithelial lesions (cervical dysplasia). HPV vaccination in adolescents is an important measure to prevent cancer [4, 5]. To date, most HPV vaccination programmes target adolescent girls and/or boys, while some countries have extended HPV vaccination catch-up programmes to adults [6]. In Europe, three HPV vaccines are currently approved: bivalent, quadrivalent and nonavalent. All three HPV vaccines include virus-like particles of the high-risk oncogenic HPV types 16 and 18, and the nonavalent HPV vaccine comprises the five additional (oncogenic) HPV types 31, 33, 45, 52 and 58. Although HPV vaccination of adolescents showed beneficial effects in the general population, it is unclear whether and to what extent the HPV vaccine offers protection to an immunocompromised population, such as individuals with organ transplants, stem cell therapy or populations under immunomodulatory therapy. Immunocompromised individuals have a potentially higher risk for infectious diseases and certain cancers compared to the general population, and studies on HPV suggest that immunocompromised individuals are at an increased risk for HPV related diseases (e.g. cervical cancer) [7-12]. While existing evidence syntheses on HPV vaccination in immunocompromised individuals primarily focuses on populations with human immunodeficiency virus (HIV) [13-15], there is no comprehensive systematic review on other immunocompromised populations [16-18].