GRADE: 20-valent pneumococcal conjugate vaccine (PCV20) for adults aged 19–64 years with underlying medical conditions or other risk factors

Introduction

On October 21, 2021, the ACIP recommended use of 20-valent pneumococcal conjugate vaccine (PCV20 [Prevnar 20, Wyeth Pharmaceuticals LLC, a subsidiary of Pfizer Inc.]) alone or 15-valent pneumococcal conjugate vaccine (PCV15 [Vaxneuvance, Merck Sharp & Dohme Corp.]) in series with 23-valent pneumococcal polysaccharide vaccine (PPSV23) [Pneumovax23, Merck Sharp & Dohme Corp Inc.]) for all adults aged ≥65 years, and for adults aged 19–64 years with certain underlying medical conditions or other risk factors*, who have not previously received a pneumococcal conjugate vaccine or whose previous vaccination history is unknown. A systematic review and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach was employed to guide ACIP’s deliberations regarding use of these vaccines.

Introduction Footnote

*Alcoholism, chronic heart/liver/lung disease, chronic renal failure, cigarette smoking, cochlear implant, congenital or acquired asplenia, CSF leak, diabetes mellitus, generalized malignancy, HIV, Hodgkin disease, immunodeficiency, iatrogenic immunosuppression, leukemia, lymphoma, multiple myeloma, nephrotic syndrome, solid organ transplants, or sickle cell disease or other hemoglobinopathies.

Methods

A systematic literature search was completed to review all available evidence on the immunogenicity and safety of PCV15 and PCV20 among age groups for which the vaccines were approved. Since only immunogenicity and safety data were available for PCV15 or PCV20, the search included PCV13 and PPSV23 efficacy or effectiveness studies to help interpret PCV15 and PCV20 immunogenicity study findings. Literature search for evidence on both PCV15 and PCV20 was done simultaneously given the similarities in the policy questions and given that use of both PCV15 and PCV20 were considered by the ACIP simultaneously. GRADE assessment was performed for PCV15 and PCV20 studies only. As a basis for the GRADE analysis, the policy question consisting of the population, intervention, comparison, and outcomes of interest was defined (Table 1).

Table 1: Policy question and definition of the Population, Intervention, Comparison, and Outcome for GRADE analysis

Table 1 Footnote

*Immunocompromised adults include adults with immunocompromising condition (chronic renal failure, nephrotic syndrome, immunodeficiency, iatrogenic immunosuppression, generalized malignancy, human immunodeficiency virus, Hodgkin disease, leukemia, lymphoma, multiple myeloma, solid organ transplants, congenital or acquired asplenia, sickle cell disease, or other hemoglobinopathies), CSF leak, or cochlear implant; immunocompetent adults are those without these conditions.

^†Chronic medical conditions include chronic heart/lung/liver disease, diabetes mellitus, alcoholism, and cigarette smoking.

Table 2: Outcomes and Rankings

Table 2. Footnote

*Three options: 1. Critical; 2. Important but not critical; 3. Not important for decision making

We leveraged a systematic review presented to the World Health Organization Strategic Advisory Group of Experts (SAGE) meeting in October 2020, which included literature up to March 2019 (1). To identify literature published during April 2019 to February 2021, we searched Pubmed, Medline, Embase, CINAHL, Scopus, Epistemonikos and Cochrane library databases. The search terms are included in appendix I. Search results were supplemented by an updated Pubmed search using “V114*”, “PCV15”, “PCV20”. Unpublished data were provided by the vaccine manufacturers.

Studies were included if they presented primary data on PCV20 in adults with underlying medical conditions or other risk factors†. Of the 2,499 titles screened for WHO SAGE and 923 titles screened for the updated review in 2021, 1 unpublished and 2 published PCV20 studies were included in the GRADE analysis (2-4). Characteristics of these studies are presented in appendix II. Beneficial and harmful outcomes for the GRADE assessment were selected by the ACIP Pneumococcal Vaccines Work Group calls and via an email survey in which Work Group members were asked to rank the relative importance of each outcome. Vaccine-type invasive pneumococcal disease, vaccine-type non-bacteremic pneumococcal pneumonia, vaccine-type pneumococcal mortality, and serious adverse events (SAEs) following immunization were deemed to be critical outcomes (Table 2).

Methods Footnote

^*V114 is the name used for Merck’s investigational 15-valent pneumococcal conjugate vaccine candidate

^†Alcoholism, chronic heart/liver/lung disease, chronic renal failure, cigarette smoking, cochlear implant, congenital or acquired asplenia, CSF leak, diabetes mellitus, generalized malignancy, HIV, Hodgkin disease, immunodeficiency, iatrogenic immunosuppression, leukemia, lymphoma, multiple myeloma, nephrotic syndrome, solid organ transplants, or sickle cell disease or other hemoglobinopathies

Table 3a. Summary of Studies Reporting Immunogenicity

Table 3a. Footnotes
GMR=geometric mean ratio, GMT=geometric mean titers, OPA=opsonophagocytic activity, PCV13=13-valent pneumococcal conjugate vaccine, PCV20=20-valent pneumococcal conjugate vaccine, PPSV23=23-valent pneumococcal polysaccharide vaccine

^*GMR (geometric mean ratio) is the ratio of pneumococcal OPA GMTs.Ratio calculated as [GMT (PCV20)] / [GMT (comparator vaccine)].

^†GMR noninferiority for a serotype was declared if the lower bound of the 2-sided 95% CI for the GMR for that serotype was greater than 0.5 (2-fold criterion).

^§If GMR non-inferiority was not assessed, “statistical significance” of GMTs (geometric mean titers) defined as: 95% CI of GMT point estimates did not overlap.

^¶Seroresponse: subjects with ≥4-fold rise in OPA GMT titer 30 days post-vaccination compared to pre-vaccination.

^**If seroresponsenon-inferiority was not assessed, “statistical significance” defined as: 95% CI of %serorespondersdid not overlap.

Table 3b. Summary of Studies Reporting Safety

Table 3b. Footnote
CI= confidence interval, PCV13=13-valent pneumococcal conjugate vaccine, PCV20=20-valent pneumococcal conjugate vaccine, PPSV23=23-valent pneumococcal polysaccharide vaccine, SAE=serious adverse events

Table 4. Grade Summary of Findings Table

Table 4. Footnote

^*These are all immunogenicity studies and there are no correlates of protection.

^†B7471007, Klein et al., and Hurley et al. enrolled healthy adults (some with chronic stable conditions, but focus is not those with immunocompromising or chronic medical conditions).

^§B7471007 provided primary PCV20 vs PCV13 immunogenicity outcomes for adults ≥60 and then showed non-inferiority for PCV20 in 18-49 year-olds compared to PCV20 in 60-64 year-olds. Did not directly compare immunogenicity of PCV20 vs PCV13 in 18-49 year-olds.

^¶Hurley et al. only enrolled 60-64 year-olds.

^**Number of patients based on minimum number included in immunogenicity comparisons presented; some comparisons may have had more patients than this minimum.

^††No vaccine-related serious adverse events reported; sample size relatively small.

Table 5. Summary of Evidence for Outcomes of Interest

Summary

The evidence type for use of PCV20 for adults aged 19–64 years with certain underlying medical conditions or other risk factors was determined to be 3 (low certainty of evidence). The ACIP reviewed the results of both GRADE analysis and the Evidence to Recommendations (EtR) framework in September 2021. In October 2021, the ACIP recommended use of PCV20 for adults aged 19–64 years with certain underlying medical conditions or other risk factors who have not previously received a pneumococcal conjugate vaccine or whose previous vaccination history is unknown.

Reference

1. World Health Organization. Strategic Advisory Group of Experts on Immunization 5-7 October 2020. 2020 [cited 2021 July 28]; Available from: https://terrance.who.int/mediacentre/data/sage/SAGE_eYB_October_2020.pdf?ua=1.
2. Essink B, Sabharwal C, Xu X, Sundaraiyer V, Peng Y, Moyer L, et al. 3. Phase 3 Pivotal Evaluation of 20-valent Pneumococcal Conjugate Vaccine (PCV20) Safety, Tolerability, and Immunologic Noninferiority in Participants 18 Years and Older. Open Forum Infect Dis. 2020;7(Suppl 1):S2-S.
3. Hurley D, Griffin C, Young M, Scott DA, Pride MW, Scully IL, et al. Safety, Tolerability, and Immunogenicity of a 20-Valent Pneumococcal Conjugate Vaccine (PCV20) in Adults 60 to 64 Years of Age. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 2020 Jul 27.
4. Klein NP, Peyrani P, Yacisin K, Caldwell N, Xu X, Scully IL, et al. A phase 3, randomized, double-blind study to evaluate the immunogenicity and safety of 3 lots of 20-valent pneumococcal conjugate vaccine in pneumococcal vaccine-naive adults 18 through 49 years of age. Vaccine. 2021 Sep 7;39(38):5428-35.

Appendix I. Search Strategies

Appendix II. Studies Included in the Review of Evidence