New pneumococcal conjugate vaccines (PCVs), 15- and 20-valent (PCV15 and PCV20), have been licensed for use among U.S. adults based on safety and immunogenicity data compared with the previously recommended 13-valent PCV (PCV13) and 23-valent pneumococcal polysaccharide vaccines (PPSV23). We conducted a systematic review of the literature on PCV13 and PPSV23 efficacy (randomized controlled trials [RCTs]) or effectiveness (observational studies) against vaccine type (PCV13 type or PPSV23 type, respectively), invasive pneumococcal disease (IPD), and pneumococcal pneumonia (PP) in adults. We utilized the search strategy from a previous systematic review of the literature published during the period from January 2016 to April 2019, and updated the search through March 2022. The certainty of evidence was assessed using the Cochrane risk-of-bias 2.0 tool and the Newcastle–Ottawa scale. When feasible, meta-analyses were conducted. Of the 5085 titles identified, 19 studies were included. One RCT reported PCV13 efficacy of 75% (PCV13-type IPD) and 45% (PCV13-type PP). Three studies each reported PCV13 effectiveness against PCV13-type IPD (range 47% to 68%) and against PCV13-type PP (range 38% to 68%). The pooled PPSV23 effectiveness was 45% (95% CI: 37%, 51%) against PPSV23-type IPD (nine studies) and 18% (95% CI: −4%, 35%) against PPSV23-type PP (five studies). Despite the heterogeneity across studies, our findings suggest that PCV13 and PPSV23 protect against VT-IPD and VT-PP in adults.

The 13-valent pneumococcal conjugate vaccine (PCV13) and 23-valent pneumococcal polysaccharide vaccine (PPSV23) were previously recommended for adults in the United States. To help inform discussions on recently licensed 15- and 20-valent pneumococcal vaccine use among adults, we conducted a systematic review of PCV13 and PPSV23 efficacy or effectiveness. We conducted a search on PCV13 and PPSV23 efficacy or effectiveness (VE) studies against vaccine type (VT) invasive pneumococcal disease (IPD) and VT-pneumococcal pneumonia in adults. Nineteen studies were included: 13 on VT-IPD (four on PCV13, nine on PPSV23) and eight on VT- pneumococcal pneumonia (three on PCV13, four on PPSV23, one on PCV13 and PPSV23). One randomized-controlled trial (RCT) evaluated PCV13 and observed an efficacy of 75% and 45% against VT-IPD and VT-pneumococcal pneumonia, respectively. No RCTs reported PPSV23 efficacy. PCV13 effectiveness estimates against VT-IPD ranged from 47% to 68%. Pooled PPSV23 effectiveness against VT-IPD was 45% (95% CI: 37%, 51%; I2=0%). PCV13 VE estimates against VT-pneumonia ranged from –2 to 46%. Pooled PPSV23 VE against VT-pneumococcal pneumonia was 18% (95% CI: -4%, 35%; I2=0%). Evidence suggests PCV13 and PPSV23 are effective against VT-IPD and VT-pneumococcal pneumonia in adults; this was used to inform PCV15 and PCV20 policy decisions.