Concern over Cervical Cancer Vaccine
(Ivanhoe Newswire) -- New research finds pros and cons of a cervical cancer vaccine. The findings indicate the vaccine produces antibodies against the virus that causes cervical cancer. However, the study also shows the antibody levels decrease around ovulation meaning the vaccine may be less effective during that time.
Human papillomavirus 16 (HPV16) is the virus that causes cervical cancer. Past research has shown a vaccine can protect against the infection. Most of these studies were done in women on oral contraceptives, which regulate the menstrual cycle. Researchers from the National Cancer Institute and Switzerland conducted a study to see how the vaccine works in women not on the pill.
The study included seven women who were taking oral contraceptives and 11 women who were ovulating. All of the women received the HPV16 vaccine. Researchers collected blood and cervical secretions twice a week for five weeks and looked at the different concentrations of antibodies during different phases of the menstrual cycle.
Researchers say all of the women had high levels of antibodies after receiving the vaccine. The antibody levels in the women taking oral contraceptives remained constant throughout the menstrual cycle. However, in the ovulating women, the antibody levels decreased around ovulation. Study authors say this indicates sex hormones may play a role in regulating antibody concentration in the cervix.
Study authors say due to the findings from this study, it is important for more research to focus on how effective the HPV16 vaccine would be for ovulating women. Researchers say it remains unclear if the drop in antibody level means a decrease in the vaccine's effectiveness.
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SOURCE: Journal of National Cancer Institute, 2003;95:1128-1137