The highest incidence of meningococcal infection in Europe is observed in Norway, and 80% of them are serogroup B cases. (There was an epidemic there in the 1970-80s, and the incidence was 1 in 14-21,000).
A double-blind, randomized study (170,000 people) was conducted on an outer membrane vaccine (OMV). Aluminum hydroxide was used as placebo. Vaccine effectiveness was only 57%, so it was decided not to include it in the immunization schedule.
Between 1990 and 1995, the incidence of pneumococcal bacteremia among adults in Sweden increased 2.6-fold, the same was observed in Norway.