§ Lord Marlesfordasked Her Majesty's Government:
Whether they will estimate the proportion of those who have received vaccination against influenza who have subsequently developed influenza, and the proportion of those who have developed influenza who had been vaccinated against it, in respect of this winter's influenza season to date. [HL736]
§ The Parliamentary Under-Secreatry of State, Department of Health (Lord Hunt of Kings Heath)This information is not routinely collected and would only be available through clinical trials. The content of the vaccine changes from year to year to reflect the strains of influenza virus that global surveillance predicts will be circulating. Its effectiveness therefore depends on how well the vaccine strains match those that cause disease each winter. This season there was a good match against the influenza viruses prevalent in the United Kingdom. The effectiveness of the vaccine also varies with age and with the strain of influenza. Overall, the vaccine is estimated to be around 70–80 per cent effective. Other respiratory viruses co-circulate with influenza, causing clinically similar illness and these are not prevented by influenza immunisation