The World Health Organization (WHO) also strongly advised early vaccination as the best prevention against the potentially devastating disease. “Influenza vaccines have an excellent safety record. In particular, the elderly and patients with chronic illnesses should see their doctor or health worker and get their flu vaccination,” said Dr. David L. Heymann, Executive Director at WHO Communicable Diseases branch. For healthy people, influenza normally amounts to high fever, headache and a few days in bed. However, for the elderly and chronically ill, the flu can be fatal. To save lives, WHO brings together influenza experts every year to compose a vaccine for the following year. More than 230 million vaccine doses are used annually. According to WHO, during the annual epidemics influenza infects as many as 100 million people annually in the northern hemisphere. While exact figures are unavailable for most countries, in the United States influenza kills approximately 20,000 people each year, the agency said. The elderly and children under one year of age are particularly at risk. History shows the potentially devastating consequences of the disease. The “Spanish flu” pandemic of 1918-19 claimed up to 40 million lives, while in Hong Kong, China, in 1997, one-third of infected patients died.