Volume 33, Issue 6, Pages 749-832 (4 February 2015)
Use of placebos in Phase 1 preventive HIV vaccine clinical trials
Yunda Huang, Shelly T. Karuna, Holly Janes, Nicole Frahm, Martha Nason, Paul T. Edlefsen, James G. Kublin, Lawrence Corey, M. Juliana McElrath, Peter B. Gilbert
Phase 1 preventive HIV vaccine trials are often designed as randomized, double-blind studies with the inclusion of placebo recipients. Careful consideration is needed to determine when the inclusion of placebo recipients is highly advantageous and when it is optional for achieving the study objectives of assessing vaccine safety, tolerability and immunogenicity. The inclusion of placebo recipients is generally important to form a reference group that ensures fair evaluation and interpretation of subjective study endpoints, or endpoints whose levels may change due to exposures besides vaccination. In some settings, however, placebo recipients are less important because other data sources and tools are available to achieve the study objectives.
:: Study objectives and the research context drive the design of Phase 1 preventive HIV vaccine trials.
:: The inclusion of placebo recipients enables blinding and fair assessment of study endpoints.
:: The inclusion of placebo recipients provides valuable in-study reference data.
:: Placebo recipients are less important for vaccines with extensive safety data.
:: Placebo recipients are less important when baseline data are proper as reference information.
How and why researchers use the number needed to vaccinate to inform decision making—A systematic review
Ahmed Hashim, Vica Dang, Shelly Bolotin, Natasha S. Crowcroft
The number needed to vaccinate (NNV) is a measure that has been widely used in the scientific literature to draw conclusions about the usefulness and cost-effectiveness of various immunization programmes. The main objective of this review is to examine how and why the NNV has been used and reported in the published literature.
Electronic databases were searched and records were screened against the eligibility criteria by two independent authors. We included papers that reported and interpreted NNV.
We identified 27 studies, the designs including observational studies, economic analyses, systematic reviews, and commentaries. The NNV has been used in the literature to describe three main themes: potential benefits of vaccination programmes, cost-effectiveness, and economic analyses, and modelling studies to compare different vaccination strategies.
NNV has been used in a wide variety of ways in the literature, yet there are no defined thresholds for what is a favourable NNV. Furthermore, the generalizability of the NNV is usually limited. Further work is required to determine the most appropriate use of this measure.
Interventions to increase influenza vaccination rates in children with high-risk conditions—A systematic review
N.W. Aigbogun, J.I. Hawker, A. Stewart
:: Influenza is a common cause of morbidity and mortality, and children with high-risk conditions (HRCs) are more likely to be hospitalized with influenza than previously healthy children.
:: Despite recommendations by the World Health Organization (WHO), annual influenza vaccination rates in children with HRCs have remained low, especially when compared to rates in other risk groups such as the elderly and pregnant women.
:: This systematic review identifies, describes and compares studies of interventions to improve influenza vaccination rates in children with HRCs – we found good evidence that reminder letters are effective, but weak evidence of effectiveness of other strategies or combination of strategies.
:: There is a need for further research of these interventions, possibly outside the United States, as almost all of the studies included in this review originated from there.
Asking about human papillomavirus vaccination and the usefulness of registry validation: A study of young women recruited using Facebook
Original Research Article
Bharathy Gunasekaran, Yasmin Jayasinghe, Julia M.L. Brotherton, Yeshe Fenner, Elya E. Moore, John D. Wark, Ashley Fletcher, Sepehr N. Tabrizi, Suzanne M. Garland
Australia was the first country to implement a government-funded National Human Papillomavirus (HPV) Vaccination Programme. We assessed HPV vaccine uptake comparing self-reported and Register validated estimates, and the knowledge and attitudes of young women with regards to HPV vaccination post-implementation of the programme.
Females, aged 16–25 years living in Victoria, Australia, were recruited using targeted advertising on Facebook from May to September 2010, to complete a web-based questionnaire.
Geographic distribution, Indigenous and socio-economic status of the 278 participants were representative of the target population. Overall, 210/278 (76%) had heard of HPV vaccines, with 162/278 (58%) reporting receipt of at least one dose of vaccine, and 54 (19%) unsure. Verification of HPV vaccination status of 142 consenting participants (51%) showed 71% had received at least one dose. Main reasons for vaccination were for protection against HPV infection and cervical cancer (96%) and because it was free (87%), whereas unvaccinated women were uncertain of their eligibility (50%), concerned about adverse reactions (32%), or perceived that vaccination was not needed if they were monogamous (32%).
The potential utility of a vaccination register in the context of a national programme is apparent from the large proportion of young women who were unsure of their vaccine status. HPV vaccine knowledge among participants was relatively high suggesting the national programme has successfully communicated to the majority of eligible women, the purpose and limitations of the vaccine. Vigilance is needed to ensure that young women follow through with Pap testing in vaccine eligible cohorts. The ongoing vaccination programme for pre-adolescent girls and boys should communicate to parents that those with one sexual partner can still acquire HPV and that the safety of the vaccine is now well demonstrated.