Norway has the highest incidence of meningococcal infection in Europe, and 80% of cases occur in serogroup B. (In the 1970s/80s there was an epidemic and the incidence was 1 to 14-21,000.) It was a double-blind, randomized trial (170,000 people) with an external membrane protein (OMV) vaccine was used as a placebo. The efficacy of the vaccine was only 57%, so it was decided not to be included in the vaccination schedule.Increase in pneumococcal bacteraemia in Sweden. 1997, Giesecke, Lancet
Between 1990 and 1995, the incidence of pneumococcal bacteremia among adults in Sweden increased 2.6-fold, the same was observed in Norway.