Scientists strive hard to develop new vaccines to effectively combat disease. This is a protracted process; and it takes several months to prepare a vaccine. Moreover, distribution of the vaccine is a time consuming task, and it takes months to distribute vaccine in the entire country. That is why vaccine manufacturers have to commence operations, well in advance of each flu season (Tesar, 2009).
Viruses cause influenza and other respiratory ailments. The spread of seasonal diseases varies every year and season, and in every environment. The incidence of influenza in the age group up to 19 years was estimated to vary between 0 to 46%. The average incidence of influenza, in the same age group for a period of five years, was 4.6%. In children, the rate of incidence was 9.5%. It is not possible to generalize the outcomes of isolated studies and studies on small groups, regarding the effectiveness of vaccines. In addition, such studies are difficult to interpret (Jefferson, 2006).
A tenth of those inoculated with such vaccine, experience side effects, like soreness at the site of the vaccination; and this is to a marked extent among children who are vaccinated for the first time. In addition, flu viruses change all the time and this leads to diversified virus strains. Consequently, flu vaccines have to keep on including these new strains (Tesar, 2009).
The process of manufacturing flu vaccine usually starts in the month of February, when medical experts at the World Health Organization (WHO) recommend the composition of the vaccine to be manufactured, in order to meet the flu season of winter, in the Northern Hemisphere. In respect of the Southern Hemisphere, the vaccine production starts in the month of September. Vaccines consist of antigens from three virus strains; specifically two from type A and one from type B (Tesar, 2009).
The effect of the flu vaccine varies from person to person, and these vaccines are effective amongst healthy youth. There is a