Recruitment barriers for prophylactic vaccine trials: A study in Belgium

Recruitment of volunteers is one of the main challenges in clinical trial management, and there is little information about recruitment barriers for preventative vaccine trials. We investigated both the recruitment barriers and recruitment strategies for preventive vaccine trials in Belgium. A 10 min survey was used as well as interviews of staff at all clinical trial sites in Belgium that regularly perform vaccine trials. We observed that there are successful recruitment strategies and few recruitment issues for trials involving healthy adults and those over 65 years old. However, challenges face the recruitment of paediatric populations, pregnant women, patients and the very elderly (over 85 years old). From these results, we identified three priority areas to increase recruitment for prophylactic vaccine trials in Belgium. These are: the lack of public knowledge about infectious diseases; the lack of resources of healthcare professionals to take part in clinical trials; and the burden to potential volunteers to take part in a trial. These were discussed with stakeholders and solutions were proposed.

Efficacy of human papillomavirus vaccines: a systematic quantitative review

Human papillomavirus (HPV) types cause approximately 70% of cervical cancer worldwide. Two vaccines have been recently evaluated in randomized controlled trials: the bivalent vaccine for HPV 16 and 18 (Cervarix, GlaxoSmithKline Biologicals, Rixensart, Belgium) and the quadrivalent vaccine for HPV 6, 11, 16, and 18 (Gardasil, Merck and Co, Inc, Whitehouse Station, NJ). We have performed a systematic review of all randomized controlled trials in which vaccines against HPV were compared with placebo regarding efficacy, safety, and immunogenicity. Six studies met the inclusion criteria, which included 47,236 women. The first objective in this systematic review was to assess vaccine efficacy in the prevention of cytologically and/or histologically proven lesions. And the secondary objective was the evaluation of safety and vaccine immunogenicity. Bivalent and quadrivalent HPV vaccines significantly reduced the rate of lesions in the cervix, vulva, vagina, and anogenital region, with efficacy of 93% (95% confidence interval [CI], 87-96) and 62% (95% CI, 27-70), respectively, when compared with the control groups according to intention to treat. Regarding safety, we found more symptoms in the bivalent vaccine group (35%; 95% CI, 5-73) when compared with the control groups. In regard to vaccine immunogenicity, there was seroconversion in the group that received the vaccine when compared with the placebo group in the bivalent and quadrivalent vaccines. Prophylactic vaccination can prevent HPV infection in women aged 9 to 26 years not previously infected with the HPV subtypes covered by the vaccines. To evaluate cervical cancer incidence and mortality, a longer follow-up is necessary.

Knowledge and awareness of human papillomavirus (HPV): attitudes towards HPV vaccination among a representative sample of women in Victoria, Australia

BACKGROUND

A vaccine program is underway to protect women against human papillomavirus (HPV) and thus cervical cancer. Previous studies have reported very low levels of HPV knowledge and there has been concern that preventative vaccines might not be readily accepted, given that HPV is transmitted sexually and the optimal time for vaccination is before sexual debut.

METHODS

A computer-assisted telephone survey was carried out with a representative sample of 1100 women aged 18 to 61 years, randomly selected from households in Victoria, Australia, to investigate knowledge and attitudes about HPV and attitudes towards HPV vaccination.

RESULTS

Half of the participants (51%) had heard of HPV; most reported learning about it from the media. Most women indicated they would trust their general practitioner (96.3%), a gynaecologist or specialist doctor (99.6%), or a women's health service (97.0%) for information about HPV. Few women (11.9%) had ever sought information about HPV and only 14.8% of the total sample had ever discussed HPV with a friend. Strong support was found for vaccination in general and there was also significant support for a HPV vaccine.

CONCLUSION

The present study documents ways in which women learn about HPV and indicates the potential for success of a vaccination program.