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Delaying Gardasil uptake, completion incurs infection, abnormalities
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Delayed uptake and longer times between doses of HPV vaccine accrued increased rates of infection and cervical cytological abnormalities, per data published in Journal of Infectious Disease.
“The recently approved 9-valent HPV (9vHPV) vaccine promises to provide greater protection by targeting five additional HR-HPV types (31/33/45/52/58), increasing coverage to over 90% of anogenital cancers,” Nicolas F. Schlecht, PhD, associate professor of epidemiology in the department of epidemiology and population health at Albert Einstein College of Medicine, and colleagues wrote. “However, the evidence to date from the clinical trials and national vaccination programs involved mostly lower-risk individuals with few sexual partners who were vaccinated early and were highly compliant with the three-dose vaccine schedule.”
To evaluate the efficacy of the three-dose quadrivalent (4vHPV; Gardasil, Merck) vaccine in high-risk areas, the investigators enrolled 1,139 sexually-active teenage girls who attended the Mount Sinai Adolescent Health Center in New York City to receive 4vHPV. The investigators collected cervical and anal specimens during the vaccination period and performed testing for HPV positive cells with L1-PCR assay. They further assessed the association between delayed vaccination between doses and time to completion of the triple dose series schedule and the risk for HPV infection and cervical cytological abnormalities. In addition, enrolled adolescents completed a self-report questionnaire of sexual behaviors, including history and safe-sex practices.
Assay analysis showed that adolescents who had received one or more doses of 4vHPV before enrollment had significantly fewer incidences of contracting cervical HPV6/11/16/18 (incidence rate ratio [IRR] = 0.2; 95% CI, 0.1-0.4) and HPV31 (IRR = 0.4; 95% CI, 0.2-1) and HPV45 (IRR = 0.3; 95% CI, 0.1-0.6). Lower incidences of anal HPV6/11/16/18 were less prevalent among adolescents who received doses prior to enrollment as well (IRR = 0.4; 95% CI, 0.2-0.7). An increased HR for cervical HPV6/11/16/18 infection (HR = 2.9; 95% CI, 1-8) and associated cytological abnormalities (HR = 4.5, 95% CI, 0.7-26) occurred in adolescents aged 15 years or older who delayed immunizations and took 12 or more months to complete the triple dose 4vHPV series.
Further, adolescents who had received at least one dose prior to enrollment were more likely to have become sexually active at a younger age, used hormonal contraceptives and emergency contraception; however, less likely to have acquired a sexually transmitted disease or have ever been pregnant.
“We find compelling evidence for a real-world benefit of 4vHPV vaccination in sexually-active minority, inner-city adolescent and young adult women against cervical and anal HPV infection with vaccine targeted types, as well as for HPV31 and 45,” the researchers wrote. “Nevertheless, we see that delayed completion of the 3-dose vaccine schedule among women immunized at 15 years and older is associated with increased risk of incident infection or re-infection with anogenital HPV6/11/16/18 and risk of associated cytological abnormalities.
“The implication of these data is that the cohort of women receiving the HPV vaccine at older ages will need active screening to prevent cervical cancer.” – by Kate Sherrer
Disclosures: Schlecht reports previous advisory roles with Merck, GlaxoSmithKline and PDS Biotechnology, and is an investigator for Merck & Co.’s Investigator-Initiated Studies Program.
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