Cost-Effectiveness of Vaccinating Immunocompetent ≥65 Year Olds with the 13-Valent Pneumococcal Conjugate Vaccine in England

Abstract

Background: Recently a large clinical trial showed that the use of 13-valent pneumococcal conjugate vaccine (PCV13) among immunocompetent individuals aged 65 years and over was safe and efficacious. The aim of this study was to assess the cost-effectiveness of vaccinating immunocompetent 65 year olds with PCV13 vaccine in England. England is a country with universal childhood pneumococcal conjugate vaccination programme in place (7-valent (PCV7) since 2006 and PCV13 since 2010), as well as a 23-valent pneumococcal polysaccharide (PPV23) vaccination programme targeting clinical risk-groups and those ≥65 years.

Method: A static cohort cost-effectiveness model was developed to follow a cohort of 65 year olds until death, which will be vaccinated in the autumn of 2016 with PCV13. Sensitivity analysis was performed to test the robustness of the results.

Results: The childhood vaccination programme with PCV7 has induced herd protection among older unvaccinated age groups, with a resultant low residual disease burden caused by PCV7 vaccine types. We show similar herd protection effects for the 6 additional serotypes included in PCV13, and project a new low post-introduction equilibrium of vaccine-type disease in 2018/19. Applying these incidence projections for both invasive disease and community-acquired pneumonia (CAP), and using recent measures of vaccine efficacy against these endpoints for ≥65 year olds, we estimate that vaccination of a cohort of immunocompetent 65 year olds with PCV13 would directly prevent 26 cases of IPD, 69 cases of CAP and 15 deaths. The associated cost-effectiveness ratio is £257,771 per QALY gained (using list price of £49.10 per dose and £7.51 administration costs) and is therefore considered not cost-effective. To obtain a cost-effective programme the price per dose would need to be negative. The results were sensitive to disease incidence, waning vaccine protection and case fatality rate; despite this, the overall conclusion was robust.

Conclusions: Vaccinating immunocompetent individuals aged ≥65 years with PCV13 is efficacious. However the absolute incidence of vaccine-type disease will likely become very low due to wider benefits of the childhood PCV13 vaccination programme, such that a specific PCV13 vaccination programme targeting the immunocompetent elderly would not be cost-effective.

Fig 1. Observed and projected incidence for invasive pneumococcal disease caused by the PCV7 vaccine types per 100.000 persons for the epidemiological years 2002/03 until 2019/20 in three age groups 65–74 (black), 75–84 (light grey) and 85 and over (dark grey line).

Future projections, see text, are shown by a dotted line.

Fig 2. Observed and projected incidence for invasive pneumococcal disease caused by the PCV13 minus PCV7 vaccine types per 100.000 persons for the epidemiological years 2002/03 until 2019/20 in three age groups 65–74 (black line), 75–84 (light grey line) and 85 and over (dark grey line).

Future projections, see text, are shown by a dotted line. The incidence in 2018/19 and 2019/20 will continue into the future.

Fig 3. Observed incidence rate ratios for PCV7 vaccine types and PCV13 minus PCV7 serotypes in the three years after vaccination compared to the four years before vaccination (2002/03 to 2005/06 for PCV7 and 2007/08 to 2010/2011 for PCV13 minus PCV7).

The dark shaded bars represent PCV7 and the light shaded bars PCV13 minus PCV7 types.

Fig 4. Observed and projected incidence for community acquired pneumonia caused by PCV7 vaccine types per 100.000 for the epidemiological years 2008/09 until 2019/20 in three age groups 65–74 (black line), 75–84 (light grey line) and 85 and over (dark grey line).

Model projections, see text, are shown by a dotted line. The incidence in 2018/19 and 2019/20 will continue into the future.

Fig 5. Observed and projected incidence for community acquired pneumonia caused by PCV13 minus PCV7 vaccine types per 100.000 for the epidemiological years 2008/09 until 2019/20 in three age groups 65–74 (dark line), 75–84 (light grey line) and 85 and over (dark grey line).

Model projections, see text, are shown by a dotted line. The incidence in 2018/19 and 2019/20 will continue into the future.