Role of pneumococcal vaccination in prevention of pneumococcal disease among adults in Singapore

Abstract

The burden of disease associated with Streptococcus pneumoniae infection in adults can be considerable but is largely preventable through routine vaccination. Although substantial progress has been made with the recent licensure of the new vaccines for prevention of pneumonia in adults, vaccine uptake rates need to be improved significantly to tackle adult pneumococcal disease effectively. Increased education regarding pneumococcal disease and improved vaccine availability may contribute to a reduction in pneumococcal disease through increased vaccination rates. The increase in the elderly population in Singapore as well as globally makes intervention in reducing pneumococcal disease an important priority. Globally, all adult vaccines remain underused and family physicians give little priority to pneumococcal vaccination for adults in daily practice. Family physicians are specialists in preventive care and can be leaders in ensuring that adult patients get the full benefit of protection against vaccine-preventable diseases. They can play a key role in the immunization delivery of new and routine vaccines by educating the public on the risks and benefits associated with vaccines. Local recommendations by advisory groups on vaccination in adults will also help to tackle vaccine preventable diseases in adults.

Keywords: adults; invasive pneumococcal disease; pneumococcal vaccine; pneumonia.

Figure 1

Functional immune responses for pneumococcal serotype 1 (GMT) in the pivotal noninferiority trial (Study 004) measured pre- and post-vaccination using a functional OPA assay. Notes: Antibodies were determined before first vaccination (pre-dose 1), 1 month after vaccination (1 month post), and 12 months after first vaccination (12 months post); and before the second vaccination 3–4 years later (pre-dose 2) and 1 month after the second vaccination (post-dose 2). An OPA titer that correlates with protection has not been defined. The dark straight line at GMT ∼140 represents the minimum GMT peaks attained following first dose of PCV13 to help understand amplification of response following revaccination. This demonstrates that PCV13 primed the immune system for a booster response to subsequent vaccination with either vaccine. In contrast, the PPSV23 vaccine inhibited the response to a second dose of the same vaccine, and this was seen for all of the serotypes (serotype 1 is shown in figure as an example). Reproduced from Paradiso PR. Pneumococcal conjugate vaccine for adults: a new paradigm. Clin Infect Dis. 2012;55(2):259–264, by permission of Oxford University Press. Abbreviations: GMT, geometric mean titer; OPA, opsonophagocytic activity; PCV13, 13-valent pneumococcal conjugate vaccine; PPSV23, 23-valent pneumococcal polysaccharide vaccine.

Figure 2

Functional immune responses for pneumococcal serotype 1 (GMT) in the pivotal noninferiority trial (Study 3005) measured pre- and post-vaccination using a functional OPA assay. Notes: Study 3005 enrolled PPSV23 exposed individuals (mean age 77 years) to receive either PCV13 or PPSV23 again. Subjects were reimmunized 1 year later with PCV13 regardless of whether they had received PCV13 or PPSV23 the previous year. Antibodies were determined before first vaccination (pre-dose 1), 1 month after vaccination (post-dose 1), before the second vaccination (pre-dose 2), and 1 month after the second vaccination (post-dose 2). Study 3005 showed that PPSV23 also blunted the response to a dose of the conjugate vaccine (serotype 1 is shown in figure as an example). Reproduced from Paradiso PR. Pneumococcal conjugate vaccine for adults: a new paradigm. Clin Infect Dis. 2012;55(2):259–264, by permission of Oxford University Press. Abbreviations: GMT, geometric mean titer; OPA, opsonophagocytic activity; PCV13, 13-valent pneumococcal conjugate vaccine; PPSV23, 23-valent pneumococcal polysaccharide vaccine.