A hundred years ago, infectious diseases were the main cause of death worldwide, even in the most developed countries. However the development of vaccines and the application of mass immunisation programs have proven successful in controlling or even eliminating diseases. Thus, before a vaccination program eliminated all natural occurrences of smallpox in 1977, the disease threatened 60% of the world’s population and killed one out of four victims. Between 1999 and 2003, measles deaths dropped worldwide by almost 40% due to vaccination.1 Vaccination is one of the most cost-effective health-care investments available. Based on data in developed countries there is an order of magnitude multiplier in savings in health-care per dollar invested in a vaccine dose.1 For developing countries the outcome is seen in greatly increased survival rates. However immunisation must be maintained to be effective. History shows that a decrease in coverage leads to the re-appearance of diseases in a previously protected population.2 In maintaining immunisation it is necessary to have continuous upgrading as drug resistant strains develop and potency decreases. Thus, in the case of the most common type of influenza virus, A (H3N2), vaccines are updated on an annual basis by the World Health Organization ( WHO) because the virus evolves so quickly. A committee of scientists meets twice a year to select the strains for use in the vaccine for the next influenza season. One of the serious challenges to creating influenza vaccines is that the global migration of viruses has been a mystery. Recent research on worldwide samples of the H3N2 virus has identified different strains and traced their movement patterns out of the East and South-East Asia circulation network to Europe and North America and then to South America.3 Once viruses leave East and Southeast Asia they rarely return but, for a variety of reasons, they continue to circulate year –round in East and Southeast Asia, serving as a source for the rest of the world. Surveillance within E-SE Asia will enable the characteristics of viruses elsewhere to be forecast each year leading to improved vaccines. In the case of avian influenza, vaccines have been produced based on whole, inactivated virus particles of H5N1 strains from outbreak regions. These have yet to be used for vaccination, but there is widespread concern that the viral strain that could cause a pandemic will be a mutated form, invalidating the stockpiles based on the current strain. However, since large scale vaccine production is not expected to commence until about three to six months following the emergence of a pandemic virus, the vaccine could be updated using existing facilities Should a pandemic occur the available supplies will be used in developing countries as manufacturing capability for avian influenza virus is overwhelmingly concentrated in Europe and North America. Current production capacity- estimated at around 300 million doses of trivalent seasonal vaccine per year falls far below the demand that could arise during a pandemic. It is not easy to increase capacity by setting up plants in developing countries, since vaccine manufacturing by standard methods is often more challenging than manufacture of therapeutic medicines and strict quality control is necessary. China is a notable exception for avian flu vaccine but India and Thailand have vaccine production for other diseases .A strong driver for increased research is that new approaches to vaccine development may allow more extensive production facilities in developing countries.