This special issue of the journal Philosophical Transactions of the Royal Society B: Biological Science explores how vaccines can fulfil their full potential for addressing global health challenges. It charts the progress to date, reviewing successes as well as challenges in the development and distribution of both human and veterinary vaccines.

The articles describe how vaccines can help mitigate and treat the world's major infectious diseases such as malaria, tuberculosis and HIV/AIDS, as well as chronic diseases, such as cancer. They explore vaccine policy and financing, ways to accelerate the development of new vaccines, issues surrounding public acceptance, and the logistics of getting vaccines to where they are needed. Also discussed is the use of vaccines to treat diseases in livestock — making an important link between health interventions, agricultural output and economic consequences.

The papers in this issue were presented at the meeting, 'New vaccines for global health', held at the Royal Society in London, United Kingdom, in November 2010.

This journal article, written by three researchers in Trinidad and Tobago, looks at malaria in the Caribbean. It asks why there are still outbreaks — including a big one in Jamaica in 2006/2007 — when the disease was allegedly eliminated in the late 1950s. The authors review malaria and vector data from across the Caribbean, summarising the pattern of imported cases as well as indigenous ones.

They identify three essential conditions for malaria transmission: presence of the vector, imported organisms and susceptible human hosts — all of which the authors show still exist across the Caribbean.

The authors suggest specific actions for regional policymakers to combat malaria. These include enhancing vector control skills, strengthening surveillance with new technologies, upgrading malaria therapy, increasing prevention strategies such as bed nets and raising public awareness of malaria. They emphasise that the role of climate change must be considered too, saying that rising temperatures could lead to new malaria vectors entering and colonising Caribbean islands and transmitting malaria on a major scale. But the authors are also careful to point out that the link to climate change is uncertain and remains contested in scientific circles.

Paul Reiter, a researcher on insects and infectious disease at the Institut Pasteur in France, is not convinced that climate change will cause a rise in malaria in tropical regions. In this opinionated review he sets out to dispel widely held "common misconceptions" about the effect of climate variability on future transmission.

To do so, he examines the history of malaria. He finds that in the past, contrary to expectations, climate has often not affected the transmission of the malaria parasite. Researchers claim that the Anopheles mosquito that carries the parasite cannot survive extreme temperatures, yet Reiter cites examples of the mosquito finding ways to adapt. In Sudan, for example, they can survive temperatures of over 55 degrees Celsius by hiding in buildings in daytime and only feeding after midnight.

Reiter's main disagreement with prediction models is that they only look at how one climate variable, temperature, is likely to interact with mosquito populations. Temperature, rainfall and humidity are interconnected and cannot be analysed separately, he says. The ecology of mosquitoes and humans is too complex to predict future malaria prevalence and incidence from temperature alone, he adds.