Friday April 25 2008
Human papilloma virus
A third of parents could refuse to allow their teenage daughters to receive a new cervical cancer vaccination, The Daily Telegraph reports today. Results from a study show that a “significant proportion of parents will not give permission for their child to receive the injection”, the newspaper says. It works by stopping the spread of the human papilloma virus (HPV), a primary cause of cervical cancer. The newspaper adds that “scientists estimate it will prevent 70% of all cases of cervical cancer, which kills about 1,000 women every year”.
This story is based on a study in two NHS primary care trusts in Greater Manchester. Although the study indicates that high levels of uptake of the first two doses of the three-dose programme are possible, these estimates may not be indicative of the national vaccination programme. High levels of coverage will need to be achieved for the vaccine to have maximum effect and this study highlights some of the barriers that will need to be tackled to achieve this. After routine vaccination for those aged 12 and 13 is introduced in September, the Department of Health plans a two-year catch-up campaign in Autumn 2009, for all girls up to 18.
Where did the story come from?
Dr Loretta Brabin and colleagues from the University of Manchester, Stockport and Bury Primary Care Trusts and the Greater Manchester Health Protection Unit carried out this research. The study was funded by the University of Manchester and GlaxoSmithKline. The authors report that the research was conducted independently of the funders. The first author was funded by the Max Elstein Foundation. It was published in the peer-reviewed British Medical Journal.
What kind of scientific study was this?
This was a prospective cohort study assessing the feasibility and acceptability of the HPV vaccine being given to adolescent girls.
The researchers asked 10 primary care trusts (PCTs) in Greater Manchester to participate in their study, and only two agreed. The PCTs were responsible for providing the bivalent HPV vaccine (the vaccine that targets two HPV strains) in the 36 secondary schools in their areas. The PCTs planned to give the vaccine in three doses, with the second and third doses being given one and six months after the first. The eligible pupils were 2,817 girls aged 12 to 13 (school year 8). Their parents were informed about the study and given an educational flier about the vaccine, details about parents’ information evenings, a slip on which to record reasons for refusal, and a slip asking for consent for a follow-up questionnaire by post, including pre-paid envelopes for reply. Parents were also sent reminders by post. Missed vaccination appointments could be rescheduled.
The researchers obtained anonymous details about the uptake of the first two doses of the vaccine from child heath departments. They also obtained information about the type of school, the ethnic makeup of the school population and whether school meals were available. The researchers then looked for relationships between uptake of the vaccine and characteristics of the schools.
What were the results of the study?
Among the 2,817 participants, 71% received the first vaccination and 69% received the second dose. About 8% of parents refused the vaccination completely, 20% failed to reply to the invitation and 1% agreed to vaccination, but their daughter did not receive it. About 16% of girls who received the first vaccination did not receive it at the original scheduled time and 24% of those who received the second vaccination did not receive it at the scheduled time. No serious side effects of the vaccinations occurred.
Vaccine uptake was lower in schools with higher proportions of girls who were eligible for school meals and in schools with higher proportions of ethnic minorities. The most common reason given by parents for refusing the vaccination was insufficient information about the vaccine and its long-term safety. Other reasons included not wanting to participate in a research study, wanting to wait for the national HPV vaccine programme or preferring the quadrivalent vaccine. Fewer parents gave reasons relating to their daughter’s age (10%) or the effect of the vaccine on adolescent sexual behaviour (3%).
What interpretations did the researchers draw from these results?
The researchers concluded that it was possible to obtain an acceptable level of uptake of the first two doses of the bivalent HPV vaccine among adolescent girls. They note that the success of the vaccination programme will depend on uptake of the third dose.
What does the NHS Knowledge Service make of this study?
This study gives us some idea of what the uptake rates of the HPV vaccine by adolescent girls might be. However, there are aspects of this study that should be taken into account when extrapolating this study to the general population:
- The fact that this was a research study deterred some parents from taking part and they may have been more likely to take part in a national programme.
- This study used the bivalent vaccine. There is also a quadrivalent vaccine and uptake of this vaccine might differ. It is as yet unclear which vaccine will be used in the UK national programme.
- This study was conducted in two areas in Greater Manchester. Uptake rates may differ in different areas with different population characteristics.
- Although 10 PCTs were asked to participate, eight refused and the reasons for this were not clear. Two schools within the PCT areas that did agree refused to participate on religious grounds, but other schools from the same religious denomination did agree to participate.
This study indicates that the high rates that need to be achieved for vaccination programmes to be effective may be feasible in consenting schools. However, it’s the overall rate of uptake in the country as a whole that will determine the effectiveness of a national campaign.
Sir Muir Gray adds...
The benefits of prevention are always in the distant and, for many people, unimaginable, future, so the attraction of the preventive offer does not appeal to all.