Declining Genital Warts in Young Women in England Associated With HPV 16/18 Vaccination: An Ecological Study

Abstract

Background. Diagnoses of genital warts (GW) in genitourinary medicine (GUM) clinics have been increasing in England for many years. In 2008, an HPV immunization program began with a bivalent vaccine (Cervarix). This was expected to markedly reduce infections and disease due to human papillomavirus (HPV) 16/18 but not HPV 6/11 infections or disease. However, from 2009 to 2011 there were decreases in reported diagnoses of GW in young females at GUM clinics.Methods. Using data from GUM clinics and a sample of general practices (GPs) throughout England, we analyzed rates of GW diagnoses by age, year of diagnosis, and estimated immunization coverage.Results. The overall reduction in GW diagnoses at GUM clinics between 2008 and 2011 was 13.3% among 16- to 19-year-old females, with the greatest decline of 20.8% in 17-year-olds. Declines were positively associated with estimated immunization coverage. A similar pattern was seen in GP diagnoses, but not among older women, and for other GUM consultations.Conclusions. Several factors might contribute to declines in GW. However, the size and pattern of the declines strongly suggest that we are observing an unexpected, moderately protective effect of HPV 16/18 vaccination against GW.

Reduction in cervical intraepithelial neoplasia in young women inBritishColumbia after introduction of theHPVvaccine: An ecological analysis

“…6 Data from Australia, the United States and the United Kingdom have shown that the vaccine is effective, with population level reductions in rates of genital warts, HPV and cervical cancer lesions. [7][8][9][10] Recent data from a populationbased study in the US, where HPV vaccine uptake has been <40%, found a reduction in HPV vaccine-type prevalence from 11.5% to 5.1% pre-and post-vaccine, respectively. 11 In Canada, between 2007 and 2009 all provinces and territories launched school-based HPV vaccine programs.…”

Cost-effectiveness of two-dose human papillomavirus vaccination in Singapore

“…(21,22,73) This additional cross-protection against these low-risk HPV types was not included in our model and therefore the current results are likely to be a conservative estimate of the relative effectiveness of AS04-HPV-16/18v versus 4vHPV.…”

“…(9, 10) Cost of screening (SGD [15][16][17][18][19][20][21][22][23][24] is paid out of pocket, except for low-income citizens aged above 40 years, who have been fully subsidised since 2014. (11) Opportunistic screening is sometimes also provided for free through charitable organisations.…”

“…(4) Recent studies have suggested that AS04-HPV-16/18v also provides moderate cross-protection against persistent infection by HPV-6 and HPV-11. (21)(22)(23)(24) The cost-effectiveness of both AS04-HPV-16/18v and 4vHPV has been evaluated in a number of countries in order to establish the value of introducing nationwide immunisation programmes, (25)(26)(27)(28)(29) in accordance with the World Health Organization's (WHO) recommendation to first establish the cost-effectiveness of a new vaccine in the country before introduction. (30) While the effectiveness and cost-effectiveness of the three-dose vaccine regimens have been evaluated for Singapore, (31,32) there are no such cost-effectiveness studies on the two-dose vaccine regimens to our knowledge.…”

How to best measure the effectiveness of male human papillomavirus vaccine programmes?

“…In addition, where 4vHPV coverage of the target female population has been high, a parallel reduction in genital warts has been observed in heterosexual males: a consequence of herd protection [15]. Surprisingly, decreases in the rates of genital wart diagnoses among vaccine-eligible females and same-aged males has been observed in England following 2vHPV vaccination [16]. Moderate 2vHPV vaccine efficacy against low-risk HPV types, through cross protection or cell-mediated immunity, may help to explain this observation [17].…”