[Issues in vaccination against influenza A in Spain]

Given the threat of an avian influenza A (H5N1) pandemic, vaccines that could be used in a new influenza pandemic began to be developed in 2004. The possible pandemic scenarios included highly serious situations with high incidence and mortality. Due to the need for the greatest possible number of vaccines to be available in a short period of time, studies with "model" vaccines were started, which allowed the immunogenicity and safety of the vaccines to be determined before identifying which virus would cause the pandemic. The use of adjuvants also formed part of these strategies. Subsequently, studies with the pandemic A (H1N1) strain were performed and additional studies continue to be performed. The vaccination strategies adopted have not been aimed at containing the infection but rather at ameliorating its effects. The choice of candidate groups for vaccination was not made hastily but after evaluating a large body of information on the epidemiology of the disease and the characteristics of the available vaccines. The population to be vaccinated is basically the same as that recommended to undergo seasonal influenza vaccination. In the ethical context of primum non nocere special emphasis has been placed on the vaccination of health personnel. All the available information supports the safety of the adjuvants and preservatives used in some of the authorized vaccines, as stated by the World Health Organization and many other prestigious organizations. So far 65 million doses have been administered throughout the world and the various adverse events detected by surveillance systems have been similar to those observed with other influenza vaccines and those that could be expected among millions of persons. Lessons must be drawn from the course of the present pandemic and the strategies used to deal with this situation as there will be other pandemics.