Determination of Antibody Responses of Elderly Adults to All 23 Capsular Polysaccharides after Pneumococcal Vaccination

Abstract

The 23-valent pneumococcal polysaccharide vaccine was formulated to prevent invasive infection in the elderly and other high-risk populations from the most prevalent Streptococcus pneumoniae serotypes. However, the immunogenicity of all 23 vaccine polysaccharides has not been fully characterized in elderly adults. We previously reported that whereas the majority of elderly subjects had vigorous immune responses to selected pneumococcal vaccine polysaccharides, a subset of elderly individuals responded to fewer than two of seven vaccine serotypes after immunization. To determine whether these elderly low responders have a general inability to respond to pneumococcal vaccine and to determine whether elderly low responders might be identified by their responses to a few polysaccharides, we measured antibody responses of elderly adults to all 23 vaccine polysaccharides after pneumococcal immunization. As a group, elderly subjects showed a significant rise after immunization in geometric mean antibody levels to all 23 vaccine serotypes. However, when individual rather than group immune responses were assessed, the 23-valent vaccine did not appear to be uniformly immunogenic in these elderly subjects. Eleven elderly subjects (20%) had twofold increases in specific antibody after vaccination to only 5 or fewer of the 23 vaccine polysaccharides, and they did not respond to the most prevalent serotypes causing invasive disease. Antibody responses to serotype 9N were found to reliably distinguish low vaccine responders from other elderly subjects. However, no particular group of vaccine polysaccharides could be used as a marker for adequate immune responses if only postvaccination sera were analyzed.

Pneumococcal Polysaccharide Revaccination: Immunoglobulin G Seroconversion, Persistence, and Safety in Frail, Chronically Ill Older Subjects

“…The analysis was performed at the Johns Hopkins University School of Medicine Reference Laboratory for Dermatology, Allergy and Clinical Immunology (Baltimore, MD) (good laboratory practice certified). The antibody serotypes for analysis were chosen based on the most frequently found serotypes associated with invasive pneumococcal infections in older individuals 14,30 . Sera preadsorbed with non‐type‐specific cell wall or C‐polysaccharide (Wyeth‐Lederle Vaccines) were added to polystyrene microtiter plate wells that had been previously coated with type‐specific pneumococcal polysaccharide.…”

Changing Epidemiology of Invasive Pneumococcal Disease Among Older Adults in the Era of Pediatric Pneumococcal Conjugate Vaccine

“…Two other studies have shown serotype 3 to be associated with excess mortality, 31,32 and in the polysaccharide vaccine, serotype 3 has been shown to have relatively poor immunogenicity for patients aged 65 years or older with chronic conditions. 25,33 Therefore, an expanded valent conju-gate vaccine that included serotype 3 may be of additional benefit to older adults if it could reduce transmission of this serotype.…”

Immunogenicity of Pneumococcal Vaccine in Renal Transplant Recipients—Three Year Follow‐up of a Randomized Trial

“…However, a protective titer of 0.35 lg/mL has been estimated through pooled analysis of vaccine efficacy studies with invasive disease endpoints and is discussed in the WHO technical report (15). Additionally, studies of pneumococcal vaccination in the elderly have shown a twofold response to be significant (17). Therefore, we chose a conservative and strict measure of response as a twofold rise in titer and an absolute titer greater than 0.35 lg/mL.…”