EtR framework for PCV20 use in children aged <2 years

About

The Evidence to Recommendations (EtR) frameworks describe information considered in moving from evidence to ACIP vaccine recommendations.

Summary

Question:

Should PCV20 be recommended as an option for pneumococcal conjugate vaccination according to currently recommended dosing and schedules, for U.S. children aged <2 years?

Population: U.S. children <2 years of age

Intervention: PCV20 according to currently recommended pneumococcal conjugate vaccination dosing and schedules

Comparison: PCV13 or PCV15 according to currently recommended dosing and schedules

Main Outcomes: Vaccine-type invasive pneumococcal disease; vaccine-type non-bacteremic pneumococcal pneumonia; vaccine-type acute otitis media; vaccine-type pneumococcal death; serious adverse events following immunization

Setting: U.S. children <2 years of age

Perspective: Clinical perspective

Background

On April 27, 2023, the FDA approved use of 20-valent pneumococcal conjugate vaccine (Pfizer [PCV20]) in children aged 6 weeks through 17 years. 15-valent pneumococcal conjugate vaccine (PCV15) use in children was approved and recommended by the ACIP in June 2022. Unlike the 13-valent pneumococcal conjugate vaccine (PCV13), which was first licensed for use in children, the new PCVs (PCV15, PCV20) were first licensed for use in adults in 2021.

Before the June 2023 ACIP meeting, either PCV13 or PCV15 was recommended for routine use in all infants aged <2 years as a 4-dose series at ages 2, 4, 6, and 12–15 months. Catch-up vaccination was recommended through age 59 months for healthy children, and through age 71 months for children with underlying medical conditions. The ACIP Pneumococcal Vaccines Work Group employed the Evidence to Recommendation (EtR) framework, using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach, to guide its deliberations regarding use of PCV20 in U.S. children as an option for pneumococcal conjugate vaccination.

Public Health Problem

References in this table:1234567

Criteria Work Group Judgements Evidence Additional Information
Is the problem of public health importance? Yes

Acute Otitis Media (AOM)

  • Acute otitis media (AOM) is one of the most common causes of pediatric medical visits, and Streptococcus pneumoniae is one of the most common bacterial causes of AOM (1, 2). Based on U.S. insurance claims data from 2014–2018, the incidence of all-cause AOM was approximately 77,000 per 100,000 person-years in children aged <2 years, 41,000 per 100,000 person-years in children aged 2–4 years, and 9,200 per 100,000 person-years in children aged 5–17 years (1, 3, 4).
  • In a 2015-2019 cohort study of children aged 6-36 months in Rochester, New York, 24% of children with clinically-diagnosed AOM had pneumoniae isolated from culture; 9.3% with pneumococcal AOM had PCV13+6C type; 8.2% had 2 additional serotypes included in PCV15; and 23.5% (includes serogroup 10 instead of 10A and serotypes 15B/C instead of serotype 15B) had 5 additional serotypes included in PCV20 (5).
  • According to data from 2016–2018, estimated outpatient AOM visits for children aged <17 years due to additional serotypes contained in PCV20 but not in PCV13 are estimated to be 39,700–54,300 per 100,000 person-years, resulting in 34,000–46,400 antibiotic prescriptions per 100,000 person-years (6).

Pneumonia

  • Based on U.S. insurance claims data in 2014, the incidence of all-cause pneumonia was the highest in children aged <5 years, ranging from 2,250 (aged <1 year) to 3,990 (aged 1 year) per 100,000 person-years (7).
  • According to 2018–2019 National Inpatient Sample data, the incidence of hospitalized all-cause pneumonia in children aged <5 years ranged from 290 (children aged 2–4 years) to 680 (children aged <1 year) per 100,000 population.
  • According to data from 2016–2018, estimated outpatient pneumonia visits due to additional serotypes contained in PCV20 but not in PCV13 are estimated to be 4300 –6800 per 100,000 person-years, resulting in 3400–5300 antibiotic prescriptions per 100,000 person-years (6).

Invasive pneumococcal disease

  • After PCV13 introduction in U.S. children in 2010, invasive pneumococcal disease (IPD) rates in children aged <5 years decreased; in 2018–2019, the IPD rate was 7.2 per 100,000 population. This decrease was driven by PCV13+6C type IPD, which decreased by 89%, from 14.2 per 100,000 population in 2007-2008 to 1.6 per 100,000 population in 2018–2019.
  • In 2020, IPD rates in children aged <5 years decreased by 55% compared with 2018–2019; a 30% increase in IPD rate was observed in 2021 compared with 2020; preliminary 2022 data show that IPD rates surpassed the rates in 2018–2019 toward the end of 2022 when increases in respiratory viral infections were reported.
  • IPD rates due to 5 additional serotypes included in PCV15 but not in PCV13 and 5 additional serotypes included in PCV20 but not in PCV15 had been stable prior to the COVID-19 pandemic; in 2018–2019 these serotypes caused 17% and 15% of all IPD in children aged <5 years, respectively.
  • Most Work Group members agreed that pneumococcal disease continues to be of public health importance due to the remaining disease burden.
  • As a minority opinion, some Work Group members believed that pneumococcal disease may not have as much public health importance compared with before given the significant reductions in pneumococcal disease due to the success of pneumococcal conjugate vaccines.

Benefits and Harms

References in this table891011

Criteria Work Group Judgements Evidence Additional Information
How substantial are the desirable anticipated effects? Moderate One phase II and one phase III randomized controlled trials (RCT) evaluated the immunogenicity of PCV20 in a 4-dose series compared with PCV13 in healthy children aged <2 years (8, 9)
  • Healthy infants 42–98 days old at time of consent were enrolled and given a dose of PCV20 or PCV13 at age 2, 4, 6 and 12–15 months.
  • Serotype-specific immunoglobulin G (IgG) geometric mean concentrations (GMCs) and opsonophagocytic activity (OPA) titers (in a subset of participants) were measured 30 days after dose 3 and 4.
  • In the phase II RCT, IgG GMCs in the PCV20 group after dose 3 and 4 were numerically lower compared with the PCV13 group for the 13 shared serotypes and higher for the 7 serotypes contained in PCV20 but not in PCV13 (PCV20-unique serotypes) (9).
  • In the phase III pivotal trial for licensure, PCV20 met the non-inferiority criteria* for 8 of 13 shared PCV13 serotypes (missed for serotypes 1, 3, 4, 9V, and 23F) and 6 of 7 PCV20-unique serotypes (missed serotype 12F) as measured by the percentage of participants with IgG concentrations above predefined concentrations† after dose 3; PCV20 met the non-inferiority criteria‡ for all 13 shared serotypes and 7 unique serotypes as measured by IgG CMC ratios after doses 3 and 4.
  • Post-licensure vaccine effectiveness data against pneumococcal disease exist for PCV13.
  • There are no studies that have directly assessed PCV20 efficacy against clinical outcomes.
  • Clinical implications of the numerically lower antibody responses in PCV20 recipients compared with PCV13 recipients for the 13 shared PCV13 serotypes are unknown.
  • There are no studies directly comparing PCV20 with PCV15.
How substantial are the undesirable anticipated effects? Minimal Safety of PCV20 was assessed in four clinical trials, three in healthy children aged <2 years (8, 9, 10). Two trials also assessed immunogenicity (8, 9). The third trial (10), a phase III RCT, assessed safety of PCV20 given at age 2, 4, 6, and 12–15 months in 1,511 healthy infants enrolled at 42–98 days of age.
  • Across three trials assessing safety of 4-dose PCV series in children <2 years, serious adverse events (SAE) ≤6 months after the fourth PCV dose was reported in 101 of 2,232 participants (4.5%) in the PCV20 group and 64 of 1,717 (3.7%) in the PCV13 group; no deaths due to vaccination were reported.
  • Febrile seizures were reported in 7 (0.2%) in the PCV20 group and 2 (0.1%) in the PCV13 group: one occurred 14 days after the fourth PCV20 dose given with measles, mumps, and rubella and varicella vaccines; another occurred 7 days after the fourth PCV20 dose in a child with a diagnosis of COVID-19; all other seizures occurred >30 days after vaccination.
Do the desirable effects outweigh the undesirable effects? Favors intervention, Favors both
  • In comparing PCV20 with either PCV13 or PCV15 for routine use in children aged <2 years, some Work Group members favored PCV20 as PCV20 use is expected to prevent more disease, whereas others favored both given the uncertainties about the clinical implications of the lower antibody response of PCV20.
  • There are no data that directly compare PCV20 immunogenicity or efficacy with PCV15. PCV15 immunogenicity studies showed that PCV15 has numerically improved antibody response against serotype 3 compared with PCV13, whereas PCV20 missed one of the noninferiority endpoints against serotype 3 in the pivotal phase 3 study (8, 11).
What is the overall certainty of the evidence of effects? Effectiveness of the intervention: Moderate
Safety of intervention: Moderate
 For critical outcomes, the certainty of evidence was moderate for both effectiveness and safety of the intervention. Certainty of evidence for effectiveness was downgraded once because only immunogenicity study data were available and correlates of protection have not been established for some outcomes. Certainty of evidence for safety was downgraded once because no vaccine-related serious adverse events were reported in studies with a relatively limited sample size.

*Noninferiority for difference in percentages of participants was defined as the lower bound of 2-sided 95% confidence interval for percent difference (PCV20-PCV13)>-10%. Additional 7 serotypes contained in PCV20 but not in PCV13 were compared with a PCV13 serotype with the lowest percentage excluding serotype 3.

†Measured as the proportion of participants meeting IgG threshold value of ≥ 0.35 µg/mL except for ≥0.23 µg/ml for serotype 5, ≥0.10 µg/ml for serotype 6B, and ≥0.23 µg/ml for serotype 19A. The direct-binding Luminex® immunoassay (dLIA) that was used to measure the IgG concentration was bridged to the WHO ELISA to establish dLIA specific threshold values for each vaccine serotype that correspond to the established ≥0.35 µg/mL WHO ELISA threshold value.

‡Noninferiority for GMC ratio was defined as the lower bound of 2-sided 95% confidence interval of IgG GMC ratio (PCV20/PCV13) >0.5. Additional 7 serotypes contained in PCV20 but not in PCV13 were compared with a PCV13 serotype with the lowest percentage excluding serotype 3.

Values

Reference in this table12

Criteria Work Group Judgements Evidence Additional Information
Does the target population feel that the desirable effects are large relative to undesirable effects? Probably yes
  • There were no data on values of the target population toward inclusion of PCV20 as an option for pneumococcal vaccination.
  • However, the high vaccination coverage of 93.3% for ≥3 doses of PCV in children born during 2018–2019 by age 24 months demonstrates that the target population feels that the desirable effects of PCV vaccination outweigh the undesirable effects (12).
 Given lack of data assessing the public’s perception of PCV20, the Work Group believed that uncertainties remained regarding whether the target population feels that the desirable effects are large relative to undesirable effects.
Is there important uncertainty about or variability in how much people value the main outcomes? Possibly important uncertainty or variability, Probably no important uncertainty or variability
  • Given that there are no clinical efficacy data, uncertainties remain about the added benefit of PCV20 use.
 Some Work Group members believed that there may be important uncertainty or variability given that there are no PCV20 efficacy data against disease outcomes and given that some express vaccine hesitancy. Others believed that given the increased incidence of pneumococcal disease during past fall/winter, most would likely value use of PCV20. A minority believed that there is no important uncertainty or variability, since there are no vaccine efficacy data.

Acceptability

References in this table131415

Criteria Work Group Judgements Evidence Additional Information
Is the intervention acceptable to key stakehold-ers? Yes Findings from three web-based surveys among healthcare providers (HCP) who administer pneumococcal vaccines were reviewed.
  • Two surveys were conducted by Merck, manufacturer of PCV15 (13, 14) one by Pfizer (15), manufacturer of PCV20.
  • Pfizer’s HCP survey assessed the acceptability of potential PCV20 recommendations compared with PCV13 or PCV15. The key difference between PCV20 and PCV15 was presented as difference in pneumococcal serotype coverage to the survey participants.
    • 76% of participants responded that they would like to transition to PCV20 for children who have received at least 1 dose of PCV13 or PCV15; most of those who expressed interest in transitioning to PCV20 preferred to provide patients with protection against as many serotypes as possible.
  • One HCP survey by Merck assessed preference between two hypothetical vaccines with various attributes to understand the importance the HCPs place on each attribute (13).
    • Of the 5 vaccine attributes, immune response for the serotypes covered in PCV13 was given the most importance, followed by % coverage of serotype in IPD.
  • Another HCP survey by Merck assessed vaccine attributes between anonymized PCV products, which showed characteristics of PCV15 and PCV20 including immunogenicity study findings and availability of studies targeting children with underlying medical conditions.
    • The survey showed that >90% of respondents believed that it is important to administer pneumococcal vaccines to children aged <2 years
    • More of respondents believed that the risk of IPD is higher in unvaccinated children aged 0–12 months compared with children aged 13–24 months (73% vs. 54%)

Resource Use

References in this table161718192021

Criteria Work Group Judgements Evidence Additional Information
Is the intervention a reasonable and efficient allocation of resources? Yes
  • Findings from three economic models (Tulane-CDC, Merck, and Pfizer), which used different methods, were reviewed.
  • The Tulane-CDC and Merck models used a single birth cohort and a timeframe of 17 and 100 years, respectively. The Pfizer model used a multi-cohort model and a timeframe of 10 years (a new birth cohort introduced each year).
  • In the assessment of the 4-dose PCV series recommended for children aged <2 years, PCV20 was compared with either PCV13 or PCV15.
  • All three models used blended vaccine prices (weighted average of private and public prices) and PCV20 was based on the adult list price which was 12–16 % greater than PCV13 and PCV15.
  • All three models included indirect effects of pediatric PCV20 vaccination on invasive pneumococcal disease (IPD) incidence in adults; the Tulane-CDC model and the Pfizer models also applied indirect effects to non-invasive pneumococcal disease incidence. The Tulane-CDC model applied a reduction in disease incidence based on previously reported estimates (16) per vaccinated cohort. The Pfizer model used estimates based on CDC’s Active Bacterial Core surveillance data (CDC unpublished data) and published data (17, 18). Reductions in disease incidence were weighted by serotype coverage and gradually accrued over 10 years. The Merck model used estimates from a previous publication (19), and reduction in disease incidence accrued in the first five years and maintained at that level throughout the timeframe of the model.
  • The Tulane-CDC and Pfizer models assume that the serotype specific VE in PCV20 was the same as the serotype specific VEs in PCV15 and PCV13. The Tulane-CDC model assumes lower vaccine effectiveness (VE) for serotype 3 and serotype 19F compared with other vaccine serotypes (20). In contrast, the Merck model assumed serotype specific VE was lower in PCV20 for six serotypes (3,12F,1,4,23F,9V) compared with PCV15 after dose 3 but applied the same VE as PCV15 after dose 4 (21).
  • The base case of all three models showed that using PCV20 for routine PCV vaccination for children ranged from being cost-saving (lower costs and improved health outcomes compared to current recommendations using PCV13 or PCV15) to $125,000 (Tulane-CDC model, comparing PCV20 with PCV15) for an additional quality adjusted life year (QALY) gained.
  • All three models included one-way sensitivity analyses with either no or lower indirect effects of PCV20 pediatric vaccination on adults which showed that using PCV20 as an option for routine PCV vaccination for children would cost between $30,000–$210,000 for an additional QALY gained.
  • In one scenario in the Merck model, where it was assumed that there was re-emergence of IPD associated with the serotypes with reduced VE (serotypes 1, 4, 9V and 23F) for PCV20 vaccination strategy, PCV15 was found to be cost-saving instead of PCV20.
  • The majority of Work Group members believed that use of PCV20 for routine PCV vaccination is a reasonable and efficient allocation of resources.
  • Some members expressed concerns that findings from the cost effectiveness analyses are sensitive to the launch price.
  • Some members expressed that uncertainties with some of the model inputs (e.g., disease burden, duration of protection, serotype distribution) resulted in a range of estimates.

Equity

References in this table122223242526

Criteria Work Group Judgements Evidence Additional Information
What would be the impact of the intervention on health equity? Probably increased Disease Burden
  • Compared with White children, Black children have higher invasive pneumococcal disease (IPD) incidence (CDC Active Bacterial Core surveillance unpublished data).
    • IPD incidence decreased in both Black and White children after PCV13 introduction in 2010, and the absolute rate difference between Black and White children decreased in children aged <5 years, especially IPD due to PCV13 types.
    • Among children aged <5 years, IPD incidence remains higher in Black children compared to White children; most of the remaining difference is due to serotypes not included in PCV20.
  • Compared with children residing in the lowest percentage of census tract poverty, children residing in the highest census tract poverty had a higher IPD incidence (22).
    • The incidence rate difference between the two groups was the largest in non-PCV20 serotypes.
  • IPD rates in Native American children in 2011–2018 have been >4 times higher compared with U.S. children of all races (23).
  • A cross-sectional analysis using 2012 Kid’s Inpatient Database showed that Native American/Alaska Native children had 1.78 (95% CI = 1.23, 2.57) greater odds of hospitalization due to pneumococcal infection compared to White children(24).

Vaccine Coverage

  • According to the National Immunization Survey-Child among children born during 2018–2019, compared with children with private insurance only, children who were uninsured and those insured by Medicaid and other insurance had lower ≥3 PCV dose coverage at 24 months (12).
  • According to the North Dakota Immunization Information System (NDIIS) for years 2014 through 2018, compared with White children, a smaller proportion of Native American children were up to date with 4 doses of PCV up to date at each immunization milestone for PCV (25).
  • The demographic groups showing the lowest ≥4 dose PCV coverage at age 24 months among children born in 2014–2017 were: uninsured children (62.2%), Black, non-Hispanic children (76.5%), children living in a non-Metropolitan Statistical Area (78.6%), and children living at <133% of the federal poverty line (75.5%) (26).
  • The majority of Work Group members believed that PCV20 use would probably increase health equity, given that post-PCV13 data showed that PCV13 reduced disparities in vaccine-type pneumococcal disease, and that there are remaining disparities in pneumococcal disease burden caused by PCV20, non-PCV13 serotypes; however, some Work Group members believed that equity would probably be reduced because new interventions are likely to be accessible to wealthy communities, first. Some believed that there may be no impact on equity because remaining disparities in PCV20, non-PCV13 type disease appeared to be minimal based on IPD data.

Feasibility

Reference in this table12

Criteria Work Group Judgements Evidence Additional Information
Is the intervention feasible to implement? Yes
  • ≥3 dose and ≥4 dose PCV coverage by age 24 months has been >80% and >90%, respectively (12).
 The work group believed that, adding PCV20 as an option for pneumococcal conjugate vaccination using the currently recommended dosing and schedule is expected to be feasible.

Balance of consequences

Desirable consequences probably outweigh undesirable consequences in most settings

Desirable consequences clearly outweigh undesirable consequences in most settings

Additional Considerations

PCV20 has a favorable safety profile and is expected to protect against pneumococcal disease caused by additional serotypes that are contained in PCV20 but not in PCV13 or 15. However, since both PCV15 and PCV20 were licensed by safety and immunogenicity data only, uncertainties remain regarding the clinical implications of the immunogenicity study findings (specifically, numerically lower immunogenicity of PCV20 for the shared serotypes with PCV13 and numerically higher immunogenicity of PCV15 against serotype 3 compared with PCV13). The cost effectiveness of PCV20 use compared with current PCVs is largely dependent on indirect effects against adult disease and uncertainties remain in the price of vaccines. Thus, preferential use of PCV20 was not proposed by the Work Group. PCVs have been used in U.S. children for >20 years and have achieved high vaccine coverage, so use of PCV20 is likely to be acceptable and feasible.

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National Center for Immunization and Respiratory Diseases (NCIRD)
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  2. Lewnard JA, King LM, Fleming-Dutra KE, Link-Gelles R, Van Beneden CA. Incidence of Pharyngitis, Sinusitis, Acute Otitis Media, and Outpatient Antibiotic Prescribing Preventable by Vaccination Against Group A Streptococcus in the United States. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 2021;73(1):e47-e58.
  3. Hu T, Done N, Petigara T, Mohanty S, Song Y, Liu Q, et al. Incidence of acute otitis media in children in the United States before and after the introduction of 7- and 13-valent pneumococcal conjugate vaccines during 1998-2018. BMC infectious diseases. 2022;22(1):294.
  4. Update: pneumococcal polysaccharide vaccine usage–United States. MMWR Morbidity and mortality weekly report. 1984;33(20):273-6, 81.
  5. Kaur R, Fuji N, Pichichero ME. Dynamic changes in otopathogens colonizing the nasopharynx and causing acute otitis media in children after 13-valent (PCV13) pneumococcal conjugate vaccination during 2015-2019. European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology. 2022;41(1):37-44.
  6. King L. February 2023 ACIP meeting presentation. Pediatric outpatient ARI visits and antibiotic use attributable to serotypes in higher valency PCVs. February 2023 ACIP meeting2023.
  7. Tong S, Amand C, Kieffer A, Kyaw MH. Trends in healthcare utilization and costs associated with pneumonia in the United States during 2008-2014. BMC health services research. 2018;18(1):715.
  8. Wyeth Pharmaceuticals LLC. 20-valent Pneumococcal Conjugate Vaccine Safety and Immunogenicity Study of a 4-Dose Series in Healthy Infants. New York, New York: Wyeth Pharmaceuticals LLC; 2020.
  9. Senders S, Klein NP, Lamberth E, Thompson A, Drozd J, Trammel J, et al. Safety and Immunogenicity of a 20-valent Pneumococcal Conjugate Vaccine in Healthy Infants in the United States. The Pediatric infectious disease journal. 2021;40(10):944-51.
  10. Wyeth Pharmaceuticals LLC. 20-valent Pneumococcal Conjugate Vaccine Safety Study in Healthy Infants. New York, New York: Wyeth Pharmaceuticals LLC; 2020.
  11. Centers for Disease Control & Prevention. GRADE: 15-valent pneumococcal conjugate vaccine (PCV15) use in children aged <2 years 2022 [updated August 31, 2022. Available from: https://wcms-wp.cdc.gov/acip/grade-evidence-tables-recommendations-in-mmwr/grading-recommendations-pcv15-children-2-years.html.
  12. Hill HA, Chen M, Elam-Evans LD, Yankey D, Singleton JA. Vaccination Coverage by Age 24 Months Among Children Born During 2018-2019 – National Immunization Survey-Child, United States, 2019-2021. MMWR Morbidity and mortality weekly report. 2023;72(2):33-8.
  13. OPEN Health. Provider Knowledge, Attitude, and Preferences Towards Pediatric Pneumococcal Vaccines. 2023.
  14. Merck & Co. Inc. HCP Preferences Concerning Pediatric Pneumococcal Vaccines Report. 2023.
  15. Myers K, Pierce N, Poulos C, Arguedas A, Chilson E, Hauber B, et al. US Health Care Providers’ Preferences for Pediatric Pneumococcal Conjugate Vaccines. Preliminary Finding
  16. Stoecker C, Kobayashi M, Matanock A, Cho B-H, Pilishvili T. Cost-effectiveness of continuing pneumococcal conjugate vaccination at age 65 in the context of indirect effects from the childhood immunization program. Vaccine. 2020;38(7):1770-7.
  17. Tong S, Amand C, Kieffer A, Kyaw MH. Trends in healthcare utilization and costs associated with pneumonia in the United States during 2008–2014. BMC Health Services Research. 2018;18(1):1-8.
  18. Tong S, Amand C, Kieffer A, Kyaw MH. Trends in healthcare utilization and costs associated with acute otitis media in the United States during 2008–2014. BMC health services research. 2018;18(1):1-10.
  19. Stoecker C, Hampton LM, Link-Gelles R, Messonnier ML, Zhou F, Moore MR. Cost-effectiveness of using 2 vs 3 primary doses of 13-valent pneumococcal conjugate vaccine. Pediatrics. 2013;132(2):e324-e32.
  20. Andrews NJ, Waight PA, Burbidge P, Pearce E, Roalfe L, Zancolli M, et al. Serotype-specific effectiveness and correlates of protection for the 13-valent pneumococcal conjugate vaccine: a postlicensure indirect cohort study. The Lancet infectious diseases. 2014;14(9):839-46.
  21. CDC. Pneumococcal vaccines (ACIP Presentation Slides) 2023 [cited 2023 March 2023]. Available from: https://wcms-wp.cdc.gov/acip/acip-meetings/acip-presentation-slides-february-22-24-2023-meeting.html
  22. Kobayashi M. February 2023 ACIP meeting presentation. Evidence to Recommendations Framework (Preliminary): Use of 20-valent Pneumococcal Conjugate Vaccine in U.S. Children. February 2023 ACIP meeting2023.
  23. Littlepage SJ, Sutcliffe CG, Simons-Petrusa B, Harker-Jones M, Weatherholtz RC, Roessler K, et al. Impact of PCV13 on Invasive Pneumococcal Disease among Native Americans Less than 5 Years of Age Living on Navajo Nation. 9th International Meeting on Indigenous Child Health; September 10 and 11, 2021; Virtual2021.
  24. Nickel AJ, Puumala SE, Kharbanda AB. Vaccine-preventable, hospitalizations among American Indian/Alaska Native children using the 2012 Kid’s Inpatient Database. Vaccine. 2018;36(7):945-8.
  25. Woinarowicz M, Howell M. Comparing vaccination coverage of American Indian children with White children in North Dakota. Public Health. 2020;186:78-82.
  26. Centers for Disease Control and Prevention. ChildVaxView [updated September 28, 2020. Available from: https://www.cdc.gov/vaccines/imz-managers/coverage/childvaxview/interactive-reports/index.html.