Streptococcus pneumoniae is one of the leading causes of morbidity and mortality in children under 5. Low-income countries are disproportionally affected and data in these settings are lacking. Effective strategies to control disease include infant immunisation with pneumococcal protein-polysaccharide conjugate vaccines. However, ongoing surveillance of carriage and disease are important to understand the impact of vaccination within communities. This thesis evaluated nasopharyngeal (NP) carriage in 3 generations, following introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) in the UK. NP carriage was also compared between rural and urban Nepalese children and a novel method of delayed culture and transport was assessed. Finally, the immunogenicity of a 10-valent pneumococcal conjugate vaccine administered in a 2-dose priming schedule without a booster was compared to a 3-dose priming schedule with a booster in Nepalese infants. Key findings include carriage rates in UK children being similar to pre-PCV7 (7 valent pneumococcal conjugate vaccine) carriage rates at 47% with low carriage rates in seen in adults. PCV7 serotypes accounted for 1.5% of carriage isolates in children, 0% in parents and 15.4% in older adults. In Nepalese children carriage was higher in a rural (69.2%) compared to an urban setting (40.9%) and delayed culture and transport using silica desiccant packets (SDP) provided a reliable, albeit underestimated, estimate of carriage. Finally this author demonstrated that following primary immunisation and boosting, there was no difference in immune responses to serotypes 1, 5 and 14 with a 2 dose priming schedule compared to a 3-dose schedule. At 2-4 years of age a significantly higher proportion of vaccinees in the 2+1 group had ≥0·2µg/mL IgG for serotypes 1, 5, 6B and 18C compared to vaccinees in the 3+0 group.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:693264 |
| Date | January 2015 |
| Creators | Hamaluba, Mainga |
| Publisher | University of Aberdeen |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=230502 |
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