Lack of pneumococcal carriage in the hospitalised elderly

Abstract

There have been few surveys of Streptococcus pneumoniae and Neisseria meningitidis carriage in sick or frail elderly people who, with the very young, comprise the group who are at highest risk for pneumococcal disease. We studied pneumococcal carriage among participants in a pneumococcal immunisation study in the frail elderly. Methods Subjects aged ≥60 years were recruited from a large tertiary referral hospital in Sydney, Australia. Nose and throat swabs were collected at the time of enrolment and 12 months after immunisation. Results Before immunisation, only 1 of 315 participants was identified as a nasal carrier of S. pneumoniae; another was identified as throat carrier of N. meningitidis. None of the participants examined after immunisation was carrying either S. pneumoniae or N. meningitidis. Conclusion The low rate of pneumococcal carriage in this population of hospitalised elderly patients was unexpected. The most likely reason is that long-term carriage is rare in this population and suggests that pneumococcal disease primarily follows recent acquisition of S. pneumoniae types not associated with carriage.