 Streptococcus pneumoniae pneumococcus is a cause of worldwide morbidity and mortality and one of the most common cause of bacterial meningitis in adults. Infection with pneumococcus can be prevented with vaccination. Two pneumococcal vaccine are used in Denmark, the 23 valent polysaccharide-based vaccine 23PPV and the 13 valent of conjugate pneumococcal vaccines PCV13. 