Pandemic influenza A (H1N1) 2009 vaccination in children: a UK perspective.

Pandemic H1N1 influenza infection was common in the UK in 2009 and children were particularly vulnerable. Most cases were mild or subclinical, but there was significant mortality, predominantly in those with pre-existing disease. Despite the rapid development of monovalent pandemic vaccines, and the fast-tracked approval process, these products were not available for large-scale use until the end of the second wave of infection. Vaccine uptake was relatively low, both among children and health-care workers. The monovalent pandemic vaccines and the 2010/2011 trivalent seasonal influenza vaccines were immunogenic and effective, and they probably reduced the impact of the third wave of infection. Vaccines containing novel adjuvants enabled antigen sparing, but safety concerns could limit the future use of these adjuvanted influenza vaccines in children. Public perceptions that the threat of the pandemic was exaggerated by the authorities, and concerns about vaccine safety, might prompt an inadequate response to the next influenza pandemic, potentially compromising public health.