UK Department of Health figures show that the rate of illness in the under-four age group is three times higher than among middle-aged and elderly people. Despite this, fewer than half of the one million children in at-risk categories have been immunized. If successful, fresh attempts to improve the production process may be able to improve the levels of immunization among children.
Although the Joint Committee on Vaccination and Immunization, which advises the government, considered extending vaccination to all children earlier this year, it was decided that there was insufficient evidence to justify the change.
In the US, infant vaccination has already been recommended. The two leading flu vaccines available in the US are Aventis Pasteur's Fluzone and Powderject's Fluvirin. Despite vaccination being approved for infants over 6 months (4 years for Fluvirin), uptake in this patient population has been slow. This can be largely attributed to parents' reluctance for their children to have another vaccination in an already crowded immunization schedule.
The limited approval of Wyeth's FluMist, with it only being indicated for patients aged between 5 and 49, is believed to be the main reason for its poor market penetration, following launch in 2003. The novel method of administration, a nasally delivered spray, makes it an ideal product for the infant age group, since it reduces the reluctance of parents to expose their child to another injection.
Another problem is that the flu vaccine is currently made by growing flu virus inside a chicken egg. This limits the number of people who can use the vaccine, due to allergies. Furthermore, the current vaccine has a long production cycle. Every year, the World Health Organization has to decide which three flu strains the vaccine should protect against, and because of the long production cycle, must make its decision around August. Compounding this are the limitations on output that result from the use of eggs. As such, healthcare providers are faced with a finite supply of vaccine each year and have to decide which patient groups are most in need of immunization.
Baxter International [BAX] and Chiron [CHIR] are both working on new technologies to develop the flu vaccine. A vaccine produced without the use of avian cultures would decrease the product cycle and reduce the limits on output. Should these new technologies be successful, the opportunities for vaccination in young children would be greatly improved.