From the Journals

Model: Quadrivalent vaccine could cost effectively cut MSM’s HPV-related cancers


 

Use of a quadrivalent HPV vaccine in men who have sex with men, administered in genitourinary specialty clinics, would cost effectively provide herd immunity against the ill effects of the virus, particularly anogenital warts and male HPV-related cancers, according to an English mathematical model.

Mark Jit, PhD, a professor of vaccine epidemiology at the London School of Hygiene & Tropical Medicine, and his colleagues considered in which settings HPV vaccination delivery would have the greatest effect size; the patterns of sexual behavior in MSM leading to the transmission of HPV 6, 11, 16, and 18; and the costs and quality adjusted life year (QALY) implications of disease outcomes (Clin Infect Dis. 2016 Dec 23. doi: 10.1093/cid/ciw845).

Clinic attendance rates were based on genitourinary clinic returns in England recorded in public health surveillance data recorded between 2009 and 2012, stratified according to diagnosed HIV-positive status. Also modeled were the effects of vaccination in MSM between the ages of 16 and 40 years, according to groups aged 16-25 years, 16-30 years, 16-35 years, and 16-40 years. Models for ages on either side of 16 or 40 years were not considered because of confidentiality constraints in the former and limited specialty clinic use in the latter.

Herd protection likely would be notable in the first year, because of the breadth of the age ranges modeled, Dr. Jit and his colleagues determined. Specifically, the models predicted a 35% decline in incidence rates of anogenital warts within 5 years of initiating the vaccine across all MSM men seen in specialty clinics. If only HIV-positive MSM across the age groups were vaccinated, the models predicted a 5-year decline of 15%.

Declines predicted in HPV-related cancers would happen more slowly, because progression from infection to malignancies tends to occur over years. For example, there would be a 55% reduction over 100 years for anal cancer if all 16- to 40-year-old MSM attending specialty clinics are offered vaccination. However, the reduction rate would drop to 40% in that same time period if only HIV-positive men across the age groups were vaccinated.

Using a cost-effectiveness threshold of 20,000 British pounds (about $24,500) per QALY, with no more than a 10% probability that the incremental cost-effectiveness ratio would exceed 30,000 pounds per QALY ($36,710), Dr. Jit and his colleagues determined that using a quadrivalent HPV vaccination in MSM between ages 16 and 40 years in the specialty clinic setting would be cost effective if delivery cost an average of 63 pounds ($77) per dose.

By offering vaccination only to HIV-positive MSM between 16 and 40 years, even if the quadrivalent vaccine were to cost as much as 96.50 pounds ($118), it would still be cost effective. A nonavalent vaccine at the same price would also be cost effective, because nearly all HPV-related cancers are linked to HPV 16 and 18. However, a bivalent vaccine was not shown by the models to be cost effective in such a limited program.

The investigators theorized that HIV infection is associated with the rate of HPV-related disease progression. To simplify computation, however, their models only considered the overall cost effectiveness of offering HPV vaccination to either HIV-positive MSM or to MSM regardless of current HIV status. That could mean “the cost effectiveness of MSM vaccination may be even better than reported,” the researchers noted.

This study was funded primarily by the National Institute for Health Research and Public Health England in the United Kingdom. The authors had no relevant disclosures.

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