Understanding Pneumococcal Carriage and Disease 2017-2020

Streptococcus pneumoniae is a type of bacteria that is carried (lives) in the nose of most individuals and can sometimes go on to cause severe infections such as meningitis and pneumonia. There are over 100 types of pneumococcus, and children in the UK have been routinely immunized against pneumococcal disease since 2006. A vaccine against 13 types of pneumococcus (PCV 13) was introduced into the UK in 2010, replacing a previous version that prevented 7 types. Pneumococcal carriage in the Thames Valley region has been studied over the last 7 years with carriage rates having been shown to be reflective of potential severe pneumococcal disease and hence vaccine effect. The main purpose of this study is to see whether the pneumococcal immunization program has changed the frequency and nature of pneumococcal bacteria carried by children, as this may give a clue as to what changes in pneumococcal disease are likely to be seen in the future. In addition, this study is especially timely given the possibility of a change in the PCV 13 immunization schedule that is currently being assessed in the 'Sched3' Immunization study (NCT02482636). Obtaining accurate baseline data will be important in informing the interpretation of any subsequent data on carriage rates obtained following introduction of the new schedule. This study will enrol up to 1600 children aged 13 to 48 months living in the Thames Valley and South Midlands and which have had three doses of 13-valent pneumococcal conjugate vaccine. In addition, up to 800, 6-12 month old children who have received a priming dose of PCV13 will be recruited. The study consists of one visit done at a convenient venue (GP surgeries, educational/ play settings, or home) where a single nasal swab and an optional finger-prick blood sample for a sub-set of 632 participants, will be performed. No additional follow-up is needed. The study recruitment period will be from 2017 onwards.