Abstract
In 2003 the existing 23-valent pneumococcal vaccine (PPV23) programme for high risk groups was extended to include all ≥65 year olds in England and Wales, starting with ≥80 year olds and moving to 75-79 and 65-74 year olds by 2005. We conducted an ecological study to assess the impact of the extended PPV23 programme on serotype-specific incidence of invasive pneumococcal disease (IPD) and a case-control study to assess vaccine effectiveness (VE) using the national IPD surveillance dataset. Between 1998 and 2006 IPD incidence caused by PPV23 serotypes in the targeted age-groups was unchanged. IPD caused by the serotypes covered by the 7-valent conjugate vaccine (PCV7) introduced for children in 2006 declined in ≥65 year olds after 2006 but was offset by an increase in non-PCV7 serotypes. This increase was similar for the additional 16 serotypes covered by PPV23 and the non-PPV23 serotypes. For the VE study, vaccine history was obtained for controls (n= 1270) with non-PPV23 IPD diagnosed between November 2003 and December 2010 and a subset of cases (n= 1272) matched for age and time period. VE declined from 48% (95% confidence interval; 32-60%) within two years of vaccination to 15% (-3% to 30%) after five years. Although differences in VE by age and having risk conditions were not statistically significant the highest estimates were in the youngest age group (65-74 years) and in those without risk conditions with a VE estimate of 65% (23-84%) within 2 years of vaccination for non-risk 65-74 year olds. VE differed by serotype (p= 0.005), from -23% (-85% to 19%) for serotype 3 to 63% (29-81%) for 12F. In conclusion PPV23 was effective, particularly in healthy under 75 year olds, but protection waned after 5 years. There was no discernible impact of PPV23 on IPD incidence or PCV7-induced serotype replacement, consistent with the modest overall effectiveness, the 45% increased coverage over the former risk-based programme and lack of herd immunity from the PPV23 programme. Based on the VE estimates PPV23 was still considered a cost-effective intervention for the low risk elderly.
| Original language | English |
|---|---|
| Pages (from-to) | 6802-6808 |
| Number of pages | 7 |
| Journal | Vaccine |
| Volume | 30 |
| Issue number | 48 |
| DOIs | |
| Publication status | Published - 6 Nov 2012 |
Bibliographical note
Funding Information:Funding source: Health Protection Agency. The funder had no role in study design, data collection and analysis or preparation of the manuscript. The funder approved the submission of the manuscript. Ethics statement: The Health Protection Agency (HPA) has approval under Section 60 of the Health and Social Care Act 2001 (which has subsumed into the National Information Governance Board for Health and Social Care with Section 60 –now Section 251 of the NHS Act 2006) to process confidential information from patients for the purposes of monitoring the efficacy and safety of vaccination programmes. Conflicts of interest statement: MS has received assistance to attend scientific meetings from Pfizer and GlaxoSmithKline and research funding from Pfizer and GlaxoSmithKline. RG has received support for conference attendance from Pfizer and GlaxoSmithKline and his laboratory has received research funding from Pfizer and GlaxoSmithKline. None of the funding from Pfizer or GlaxoSmithKline was used specifically for this study. No other authors have conflicts of interest. Author Contributions: Designed the study: EM, NA, PW, RG, MS. Analysed the data: NA, EM. Wrote the manuscript: NA, EM. Commented on the manuscript: PW, RG, MS. ICMJE criteria for authorship read and met: NA, PW, RG, MS, EM. Agree with results and conclusions: NA, PW, RG, MS, EM. Database design, data and study management: PW. Culture and serotyping: RG, MS. Checking of clinical information: EM, MS.
Keywords
- 23-Valent pneumococcal polysaccharide vaccine
- Broome method
- Indirect cohort method
- Invasive pneumococcal disease
- Vaccine effectiveness
- Vaccine impact
