Human papillomavirus vaccine maintains efficacy for 4.5 years
Dr Linda Stannard, UCT/Science Photo Library
Human papillomavirus |
Immunity against human papillomavirus (HPV) is maintained for up to
4.5 years following vaccination, according to the results of a study
published online in Lancet
Oncology on 6 April.
The researchers conducted a long-term follow-up study of 776 women who
were injected with GlaxoSmithKline’s candidate cervical cancer
vaccine (Cervarix) or placebo during a primary efficacy study (Lancet 2004;364:1731).
Follow-up revealed that more than 98 per cent of women given the vaccine
had sustained levels of antibodies against HPV-16 and HPV-18 — the
subtypes responsible for 70 per cent of cervical cancers — for
up to 4.5 years after receiving the last dose. The vaccine was effective
against incident infections (96.9 per cent, 95 per cent confidence interval
81.3–99.9) and infections that had persisted for six or 12 months
(94.3 per cent, CI 63.2–99.9, and 100 per cent, CI 33.6–100,
respectively).
Cross-protection against HPV-45 and HPV-31, the third and fourth most
common HPV types associated with cervical cancers, was also observed.
The number of women reporting serious adverse events was similar in the
vaccine (4 per cent) and placebo groups (5 per cent) and none was judged
to be related or possibly related to the vaccine, say the researchers.
They conclude: “These findings set the stage for the widescale
adoption of HPV vaccination for prevention of cervical cancer.” |
The
Pharmaceutical Journal
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