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One dose of HPV vaccine protected against cervical cancer for 4 years
A single dose of the HPV16/18 vaccine maintained a durable antibody response against cervical cancer for 4 years, according to study results.
Researchers evaluated data from 390 women in Costa Rica who received the HPV16/18 vaccine (Cervarix, GlaxoSmithKline) in four dosing schedules.
The cohorts included 78 women who received one dose, 140 who received two doses separated by 1 month, 52 who received two doses separated by 6 months, and 120 who received the recommended three doses of the vaccine.
The analysis also included 113 women who were HPV16 or HPV18 seropositive prevaccination for comparison.
Four years after vaccination, 100% of women in all dosing schedules remained HPV16/18 seropositive.
Antibody levels were comparable between the women who received two doses in 6 months and those who received three doses (HPV16, geometric mean titer [GMT] ratio=0.69; 95% CI, 0.53-0.89; HPV18, GMT ratio=0.91; 95% CI, 0.68-1.22).
HPV16 GMT was 24 times higher in women who received two vaccine doses and nine times higher in women who received one dose compared with controls. HPV18 GMT was 14 times higher in women who received two doses and five times higher in women who received one dose.
“Our findings suggest promise for simplified vaccine administration schedules that might be cheaper, simpler and more likely to be implemented around the world,” Mahboobeh Safaeian, PhD, an investigator in the division of cancer epidemiology and genetics at the NCI, said in a press release. “Vaccination with two doses, or even one dose, could simplify the logistics and reduce the cost of vaccination, which could be especially important in the developing world.”
Disclosure: Researchers report royalties on US government-owned patents, royalties on government-owned HPV vaccine patents licensed to GlaxoSmithKline and Merck, and an ownership interest — including patents — in DDL Diagnostic Laboratory.