This clip is from BBC.Development of vaccine is not easy as the virus changes it's antigenicity frequently.That is why vaccine developed to-day becomes ineffective tomorrow.Treatment is mainly symptomatic.Antiviral treatment shorten the course of disease.Secondary infection by bacteria or fungus need to be treated.
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clipped from news.bbc.co.uk Flu Flu and complications linked to it kill hundreds of people in the UK each year. But despite massive investment in research into the virus, there is no cure. However, there are vaccines which have some protective effect. These are normally administered to the elderly and the vulnerable each year. But every few years a new strain of flu appears which spreads so rapidly that precautions cannot be developed in time. This can lead to pandemics which threaten millions of lives. The worst flu pandemic this century was the Spanish flu pandemic of 1918 which killed an estimated 40 million people - more than World War One.