Iacopo Baussano1, Ugyen Tshomo2, Vanessa Tenet1, Daniëlle A M Heideman3, Tshering Wangden2, Silvia Franceschi4, Gary M Clifford1. 1. International Agency for Research on Cancer, Lyon, France (I.B., V.T., G.M.C.). 2. Jigme Dorji Wangchuck National Referral Hospital, Thimphu, Bhutan (U.T., T.W.). 3. Amsterdam UMC, Vrije Universiteit Amsterdam, Cancer Center Amsterdam, Amsterdam, the Netherlands (D.A.H.). 4. Centro di Riferimento Oncologico (CRO), IRCCS, Aviano, Italy (S.F.).
Abstract
BACKGROUND: Bhutan implemented a national program for human papillomavirus (HPV) vaccination in 2010 involving girls aged 12 to 18 years and achieving nearly 90% coverage. OBJECTIVE: To estimate HPV vaccine effectiveness in a city in Bhutan. DESIGN: 2 cross-sectional surveys, 2011-2012 and 2018. SETTING: 2 hospitals in Thimphu, capital of Bhutan. PARTICIPANTS: Sexually active women aged 17 to 29 years: 1445 participants from the baseline survey and 1595 from the repeated survey. INTERVENTION: National HPV vaccination program. MEASUREMENTS: HPV was assessed in cervical cell samples by using general primer GP5+/GP6+-mediated polymerase chain reaction. Human papillomavirus types were stratified as vaccine types (HPV6/11/16/18) and nonvaccine types. Age- and sexual behavior-adjusted overall, total, and indirect (herd immunity) vaccine effectiveness (VE) was computed as (1 - HPV prevalence ratio) for HPV among all women and among unvaccinated women. RESULTS: Between the 2 surveys, the prevalence of HPV vaccine types decreased from 8.3% to 1.4%, whereas the prevalence of nonvaccine types increased from 25.8% to 31.4%. The overall and indirect adjusted VE against vaccine-targeted HPV types was 88% (95% CI, 80% to 92%) and 78% (CI, 61% to 88%), respectively. Among women younger than 27 years, who were targeted by the vaccination program, the overall and indirect adjusted VE was 93% (CI, 87% to 97%) and 88% (CI, 69% to 95%), respectively. No impact on nonvaccine HPV types was detectable. LIMITATION: Hospital-based recruitment; self-reported vaccination status. CONCLUSION: In Bhutan, the prevalence of vaccine-targeted HPV types has decreased sharply, providing the first evidence of the effectiveness of a high-coverage national HPV vaccination program in a lower-middle-income country. PRIMARY FUNDING SOURCE: Bill & Melinda Gates Foundation.
BACKGROUND: Bhutan implemented a national program for human papillomavirus (HPV) vaccination in 2010 involving girls aged 12 to 18 years and achieving nearly 90% coverage. OBJECTIVE: To estimate HPV vaccine effectiveness in a city in Bhutan. DESIGN: 2 cross-sectional surveys, 2011-2012 and 2018. SETTING: 2 hospitals in Thimphu, capital of Bhutan. PARTICIPANTS: Sexually active women aged 17 to 29 years: 1445 participants from the baseline survey and 1595 from the repeated survey. INTERVENTION: National HPV vaccination program. MEASUREMENTS: HPV was assessed in cervical cell samples by using general primer GP5+/GP6+-mediated polymerase chain reaction. Human papillomavirus types were stratified as vaccine types (HPV6/11/16/18) and nonvaccine types. Age- and sexual behavior-adjusted overall, total, and indirect (herd immunity) vaccine effectiveness (VE) was computed as (1 - HPV prevalence ratio) for HPV among all women and among unvaccinated women. RESULTS: Between the 2 surveys, the prevalence of HPV vaccine types decreased from 8.3% to 1.4%, whereas the prevalence of nonvaccine types increased from 25.8% to 31.4%. The overall and indirect adjusted VE against vaccine-targeted HPV types was 88% (95% CI, 80% to 92%) and 78% (CI, 61% to 88%), respectively. Among women younger than 27 years, who were targeted by the vaccination program, the overall and indirect adjusted VE was 93% (CI, 87% to 97%) and 88% (CI, 69% to 95%), respectively. No impact on nonvaccine HPV types was detectable. LIMITATION: Hospital-based recruitment; self-reported vaccination status. CONCLUSION: In Bhutan, the prevalence of vaccine-targeted HPV types has decreased sharply, providing the first evidence of the effectiveness of a high-coverage national HPV vaccination program in a lower-middle-income country. PRIMARY FUNDING SOURCE: Bill & Melinda Gates Foundation.
Authors: Susan Yuill; Louiza S Velentzis; Megan Smith; Sam Egger; C David Wrede; Deborah Bateson; Marc Arbyn; Karen Canfell Journal: Hum Vaccin Immunother Date: 2021-10-03 Impact factor: 4.526
Authors: Maxime Bonjour; Hadrien Charvat; Eduardo L Franco; Marion Piñeros; Gary M Clifford; Freddie Bray; Iacopo Baussano Journal: Lancet Public Health Date: 2021-04-15