The development, implementation, and continued use of new vaccines depends on several factors. Although disease burden seems like an obvious quantitative measure for setting priorities for new vaccine development and use, resources are not always allocated proportionately. This is particularly evident for diseases that are unique (or largely limited) to people in developing countries. Public pressure based on perceptions of the risks associated with a disease or vaccine, the cost of new vaccines, and the ability to incorporate them into existing vaccination programmes also need to be considered in the decision to introduce new vaccines. Vaccine manufacturers play an important part in development of new vaccines, and therefore, the issues that are important to them, namely, production, intellectual property rights, and product liability, must be addressed. By advocating rational decisions, supported by accurate information, scientists and public-health professionals can have an important role in transforming the potential of new vaccines into the reality of new vaccine-preventable diseases.

Most public-health assessments of climate-control policies have focused on long-term impacts of global change. Our interdisciplinary working group assesses likely short-term impacts on public health.

The first abnormality leading to sodium and water retention in cirrhosis is the renal tubular defect that is related to deteriorating liver function and hyperaldosteronism. With progression of liver disease and portal hypertension, renal blood flow declines because of the hepatorenal reflex, and is then maintained by the vasoactive hormonal systems. With increasing peripheral vasodilatation, intrarenal factors for maintenance of renal perfusion cause intense cortical vasoconstriction. The systemic vasoactive factors are predominantly compensatory; any attempts to counteract their action risk circulatory collapse. Future studies should be directed at intrarenal factors. The ideal drug for the treatment of portal hypertension would reduce portal pressure, increase renal blood flow, and produce insignificant changes in arterial pressure.

There is much evidence that people who had low birthweight tend to have higher blood pressure in later life. However, the mechanisms that mediate this relation are unknown. We argue that, in fetuses whose growth is impaired, synthesis of elastin in the walls of the aorta and large arteries may be deficient, and that this deficiency would lead to permanent changes in the mechanical properties of these vessels. Over a lifetime, such changes could predispose an individual to higher blood pressure, increased left-ventricular mass, and cardiovascular disease.

Homeopathy seems scientifically implausible, but has widespread use. We aimed to assess whether the clinical effect reported in randomised controlled trials of homeopathic remedies is equivalent to that reported for placebo.