In an era of high-speed recombinant genetic drugmaking, vaccine production is still primitive, little changed in 50 years.

FORBES: Broken Eggs

That could mean there is a genetic difference that determines whether the vaccine works, and that an assay might measure how effective the vaccine is in a particular patient.

FORBES: A Tough Day For AIDS Prevention

But it added there appeared to be a link but the vaccine "is likely to have interacted with genetic or environmental factors which might raise the risk of narcolepsy, and that other factors may have contributed to the results".

BBC: Narcolepsy link to swine flu vaccine investigated

Researchers in the United States have already taking steps to crack the genetic code of the virus behind the swine flu outbreak in order to produce a vaccine, U.S. officials said Wednesday.

CNN: WHO raises pandemic alert to second-highest level

Scientists are working on the genetic sequencing of the virus, as well as growing a strain that functions as a vaccine.

CNN: At CDC, war against flu doesn't stop

Microbial miseries which were untouchable using old vaccine methods because of safety concerns or scientific limitations are now treatable through genetic tinkering.

ECONOMIST: Vaccines

Meanwhile, Britain's health secretary announced Friday that his country's Health Protection Agency had sequenced the full genetic code of the H1N1 virus, the first step in producing a European prototype of a swine flu vaccine.

CNN: WHO reports big jump in swine flu cases