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Vaccine developers "should use quantitative tools to set priorities"

Policy-makers in health and biomedical research should use a quantitative model to help guide decisions about which vaccines to develop, says a major report from the Institute of Medicine in Washington, DC.(a) The report, which comes 14 years after an earlier project from the same organization to develop priority-setting methods for vaccines, sets out a model and uses it to categorize candidate vaccines, although it specifically rejects the idea of recommending any particular vaccines for development.

The focus of the report, unlike the 1985 project, is entirely on domestic health needs in the United States, but its methods are applicable to any other population. The study was requested by the US National Institutes of Health. The model weighs the costs of each candidate vaccine against its expected health gains, taking account of changes in the cost of health care that are expected to result from the vaccine as well as the costs of its development and delivery. Health benefits are measured in quality-adjusted life years (QALYs).

Under this model, candidate vaccines fall into four broad categories: Level I, "most favourable", comprising vaccines that would save money and QALYs; Level II, "more favourable", those costing less than US$ 10 000 per QALY saved, through to Level IV, which would cost more than US$ 100 000 per QALY saved. Candidates in Level I for the United States include, among others, a vaccine against cytomegalovirus for 12 year-olds, an influenza virus vaccine for the general population, a vaccine against Streptococcus pneumoniae for infants and the elderly, and therapeutic vaccines for insulin-dependent diabetes mellitus, multiple sclerosis and rheumatoid arthritis. Group IV candidates include a vaccine against Borrelia burgdoferi, among others. The report stresses that this ranking should not be taken out of context or read as a recommendation for what should or should not be developed. "Level IV candidate vaccines could be justified on several levels," it says. For example, research on such vaccines might lead to new knowledge that would benefit other vaccine development. Priorities would also be different in other populations.

The report concludes that not all vaccines will save money, but that the health benefits they might offer could still be compelling. Policy-makers may need to "shift from the expectation that vaccines are always cost-saving to an acknowledgement that the health benefits of some vaccines might be worth the cost," says the report.

(a) Committee to Develop Priorities for Vaccine Development, Institute of Medicine. Stratton KR, Durch JS, Stoto MA, eds. Vaccines for the 21st century. A tool for setting priorities. National Academy Press, Washington, DC, 1999. A prepublication summary of the report is available on the Institute of Medicine's website (http://romulus.nap.edu/readingroom/books/ vacc21).

Quick and robust PCR field test for bacteria

Investigators who need to identify the source of an outbreak of infectious disease have long sought a precise and rapid detection method that is portable and robust in the field. This method now appears to be in sight, according to a report in the journal Science.(b) Phillip Belgrader and his colleagues at the Lawrence Livermore National Laboratory in California have tested a portable battery-operated tool for performing the polymerase chain reaction (PCR) that produces results in seven minutes. The researchers believe their system could be used both for investigating outbreaks of disease and in detecting agents of biological warfare. It could also be used to investigate contamination of water or food supplies.

Until now, rapid field testing of samples has relied on immunological assays, which identify antibodies to specific infectious agents. However, many investigators would prefer to identify microbial genetic material directly, because this may give them information about the virulence of an organism and identify, for example, whether a particular antibiotic-resistant strain is present. …