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Centers for Disease Control and Prevention
National Center for Immunization and Respiratory Diseases
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RSV Vaccination in Older Adults:
Benefit -Risk Discussion
Michael Melgar , MD
Lauren Roper, MPH
Advisory Committee on Immunization Practices
February 29, 2024
There are two RSV vaccines approved in the United States
and recommended for adults aged ≥60 years, using shared
clinical decision -making.
Slide credit: https://stacks.cdc.gov/view/cdc/108883
Estimated benefits
of RSV vaccination
(single dose) with
GSK’s Arexvy and
Pfizer’s Abrysvo ,
stratified by agePotential risk of
Guillain -Barre
syndrome (GBS) after
RSV vaccination with
GSK’s Arexvy and
Pfizer’s Abrysvo
2
▪Estimated benefits
–Estimated numbers of preventable RSV illnesses over two
consecutive seasons , per 1 million vaccine doses administered to
adults 60 years and older1
•Outpatient visits, hospitalizations, intensive care unit (ICU)
admissions, in -hospital deaths
–Informed by published incidence rates, RSV surveillance data
from CDC, and estimated vaccine efficacy from clinical trials
▪Potential risk
–Informed by rate of GBS per 1 million vaccine doses
administered to adults 60 years and older1 observed in FDA
analysis of data from the FDA -CMS partnership2
–Preliminary data did not permit estimation of attributable (i.e.,
excess) risk, so observed rates are also compared with rates
expected from backgroundOverview of comparisons
1. This analysis assumes 100% uptake of RSV vaccine, with a single dose, in a cohort of 1 million older adults.
2. Analysis of administrative claims data using a 42 -day risk interval, adjusted for delays in claims data. https://bestinitiative.org/wp -content/uploads/2024/01/BEST_RSV_Safety_Older_Adults_2023 -2024.pdf
3
Estimated age distribution of national RSV -associated hospitalizations, ICU admissions, and in -
hospital deaths among adults ≥18 years, RSV -NET, 2022 –2023, compared with U.S. population
Unpublished data. Underlying rates are adjusted using multipliers for the frequency of RSV testing during each season and for the sensitivity of RSV diagnostic tests. Estimates
from 2022 -2023 are preliminary. These estimates use the same multipliers as for 2019 -2020.
*As of 2022. https://www.census.gov/popclock/ 42.9%
37.1%
58.0%
9.2%23.9%
26.8%
22.8%
13.0%20.4%
22.6%
11.3%
24.1%12.8%
13.6%
7.9%
53.7%
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%Hospitalizations
ICU admissions
In-hospital deaths
U.S. Adult Population*≥75 65-74 50-64 18-49
U.S. Adult Population *Age group, years:
4
0100200300400500600
2016-17 2017-18 2018-19 2019-20 2020-21 2021-22** 2022-23**Annual RSV -associated hospitalizations
per 100,000 population 18-49 50-54 55-59 60-64 65-69 70-74 75-79 ≥80
Unpublished data. Rates are adjusted using multipliers for the frequency of RSV testing during each season and the sensitivit y of RSV diagnostic tests.
*Estimated rates exclude recorded hospitalizations among pregnant adults.
**Estimates from 2021 -2022 and 2022 -2023 are preliminary. These estimates use the same multipliers as for 2019 -2020.
https://www.cdc.gov/rsv/research/rsv -net/index.html Estimated annual RSV -associated hospitalization rates per 100,000 adults*
aged ≥18 years by age group and year, RSV -NET, 2016 –17 to 2022 –23
Age group, years:
5
0100200300400500600
2016-17 2017-18 2018-19 2019-20 2020-21 2021-22** 2022-23**Annual RSV -associated hospitalizations
per 100,000 population 60-64 65-69 70-74 75-79 ≥80 Inputs : Estimated annual RSV -associated hospitalization rates per 100,000
adults* aged ≥60 years by age group and year, RSV -NET, 2016 –17 to 2022 –23
Unpublished data. Rates are adjusted using multipliers for the frequency of RSV testing during each season and the sensitivit y of RSV diagnostic tests.
*Estimated rates exclude recorded hospitalizations among pregnant adults.
**Estimates from 2021 -2022 and 2022 -2023 are preliminary. These estimates use the same multipliers as for 2019 -2020.
https://www.cdc.gov/rsv/research/rsv -net/index.html Age group, years:
6
▪Over the same surveillance seasons
(2016 -17 to 2019 -20, and 2022 -23):
–Calculated the proportions of hospitalized
adults in each age group who
•Were admitted to ICU
•Experienced in -hospital death
–Applied these proportions to the estimated
hospitalization rates*
–Estimated population -based rates of ICU
admission and in -hospital deathInputs : Estimated annual rates of RSV -associated ICU admission and
in-hospital death per 100,000 adults aged ≥60 years (RSV -NET)
*Unpublished data. Rates are adjusted using multipliers for the frequency of RSV testing during each season and the sensitivi ty of RSV diagnostic tests.
Estimated rates exclude recorded hospitalizations among pregnant adults.
Estimates from 2022 -2023 are preliminary. These estimates use the same multipliers as for 2019 -2020.
https://www.cdc.gov/rsv/research/rsv -net/index.html
7
05001,0001,5002,0002,500
18-49 50-64 ≥65 Annual RSV -associated outpatient visits
per 100,000 population
Age (years)Inputs : Estimated annual rates of RSV -associated outpatient visits per 100,000
adults aged ≥18 years , meta -analysis of active surveillance studies, United States
Industry -sponsored (Pfizer): McLaughlin JM, Khan F, Begier E, et al. Rates of Medically Attended RSV Among US Adults: A Systematic Review and Meta -
analysis. Open forum infectious diseases 2022 Jul; 9(7):ofac300. https://doi.org/10.1093/ofid/ofac300
8
Inputs : Summary of annual rates of RSV -associated illness
1. Industry -sponsored (Pfizer): McLaughlin JM, Khan F, Begier E, et al. Rates of Medically Attended RSV Among US Adults: A Systematic Review and Meta -analysis. Open
forum infectious diseases 2022 Jul; 9(7):ofac300. https://doi.org/10.1093/ofid/ofac300
2. CDC RSV -NET data from surveillance seasons: 2016 -17 to 2019 -20 and 2022 -23. Values are based upon the average burden -adjusted ra tes and 95% confidence intervals
over those five seasons. Unpublished data. https://www.cdc.gov/rsv/research/rsv -net/index.html
3. Kujawski SA, Whitaker M, Ritchey MD, et al. Rates of respiratory syncytial virus (RSV) -associated hospitalization among adults w ith congestive heart failure -United States,
2015 -2017. PLoS One. 2022 Mar 9;17(3):e0264890. https://doi.org/10.1371/journal.pone.0264890
4. Industry -sponsored (Pfizer): Onwuchekwa C, Moreo LM, Menon S, et al. Underascertainment of Respiratory Syncytial Virus Infection in Adults Due to Diagnostic Testing
Limitations: A Systematic Literature Review and Meta -analysis. The Journal of Infectious Diseases. 2023 July; 228(2): 173 –184. https://doi.org/10.1093/infdis/jiad012 Outcome Values
Outpatient visits Published incidence rates and 95% confidence intervals.1
Hospitalizations RSV -NET2; age -dependent rates and 95% confidence intervals are based on laboratory -
confirmed RSV infections among hospitalized adults detected through clinician -driven testing,
and are adjusted for the frequency of RSV testing among adults hospitalized with respiratory
illness and for the sensitivity of diagnostic tests (burden adjustment).3 Assumed test sensitivity
incorporates recent literature showing increased diagnostic yield from multiple specimen
types, relative to nucleic acid testing of nasopharyngeal swab alone.4 Input values are taken as
the mean burden -adjusted rates over five RSV seasons (2016 -17 to 2019 -20, and 2022 -23).
ICU admissions Mean age -dependent rates and 95% confidence intervals of RSV -associated ICU admission
from RSV -NET over five seasons2
Deaths
(in-hospital only)Mean age -dependent rates and 95% confidence intervals of RSV -associated in -hospital deaths
from RSV -NET over five seasons2
9
Outcome (RSV -Associated) Arexvy , GSK1
VE (95% CI)Abrysvo , Pfizer2
VE (95% CI)
Season 1
(months 0 -7
post -injection)Season 2
(months 13 -18
post -injection )3Season 1
(months 0 -7
post -injection)Season 2
(months 8 -14
post -injection )3
Outpatient visits4
Trial efficacy against medically -attended
RSV ARI79.0%
(54.3, 91.5)27.8%
(0, 60.4)65.2%
(36.0, 82.0)55.0%
(0, 82.0)
Hospitalizations, ICU Admissions,
and In -hospital Deaths
Trial efficacy against medically -attended
RSV LRTD/LRTI87.5%
(58.9, 97.6)552.9%
(0, 81.2)584.6%
(32.0, 98.3)675.0%
(0, 97.4)6Inputs : Vaccine Efficacy (VE)
Point estimates were used in this analysis. Uncertainty in vaccine efficacy was not incorporated into uncertainty in estimate d preventable outcomes.
Ref (Slide 18): https://www.cdc.gov/vaccines/acip/meetings/downloads/slides -2023 -06-21-23/05 -RSV -Adults -Ortega -Sanchez -508.pdf
1 GSK Phase 3 Trial; interim analysis 2023; CDC -calculated vaccine efficacy in participants ages ≥60 years
2 Pfizer Phase 3 Trial; interim analysis 2023; CDC -calculated vaccine efficacy in participants ages ≥60 years
3 Efficacy estimates are not directly comparable. Clinical trials used different outcome definitions and the follow up time in differed substantially across
trials. Further, efficacy estimates are associated with substantial uncertainty.
4 CDC -calculated VE against medically -attended RSV acute respiratory illness (ARI)
5 CDC -calculated VE against medically -attended RSV lower respiratory tract disease (LRTD)
6 CDC -calculated VE against medically -attended RSV lower respiratory tract illness (LRTI) with at least 3 lower respiratory sympto ms10
Weekly rates of RSV -associated hospitalization,* all ages,
RSV -NET, October 2018 –February 2024
*RSV -NET hospitalization data are preliminary and subject to change as more data becomes available.
Rates have not been adjusted for testing practices and underestimate actual rates of RSV -associated hospitalizations, as not all people hospitalized with respiratory illness are
tested for RSV. In addition, clinician -directed RSV testing practices may have changed over time and may differ by disease sever ity, age, and/or racial and ethnic group of
patients; trends in RSV -associated hospitalization rates across seasons should be interpreted with caution.
For more information on RSV -NET, please visit https://www.cdc.gov/rsv/research/rsv -net/index.html . 2018 -192019 -20
2020 -212021 -222022 -23
2023 -24
0123456
40414243444546474849505152123456789101112131415161718192021222324252627282930313233343536373839
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug SepWeekly RSV -associated hospitalizations
per 100,000 population
Month and MMWR Week
11
▪Clinical trials of both vaccines under -enrolled adults 75 years
and older and were under -powered to estimate vaccine
efficacy in this age subgroup.
▪Aging results in lowered immune responsiveness
characterized by impairments in both innate and adaptive
immunity (immune senescence).*
▪Adults 75 years and older might experience reduced VE
against all outcomes, compared with adults ages 60 –74 years.
▪There are no data yet available from post -licensure
observational effectiveness studies to estimate protection
among adults aged ≥75 years.Inputs: Vaccine Efficacy (VE), sensitivity analysis
Assumed VE among adults aged ≥75 years is reduced by half , compared with adults aged 60 –74 years
*Stephens LM, Varga SM. Considerations for a Respiratory Syncytial Virus Vaccine Targeting an Elderly Population. Vaccines (B asel). 2021 Jun 9;9(6):624.
https://doi.org/10.3390/vaccines9060624
12
Outcome (RSV -Associated) Arexvy , GSK1
VE (95% CI)Abrysvo, Pfizer2
VE (95% CI)
Season 1
(months 0 -7
post -injection)Season 2
(months 13 -18
post -injection )3Season 1
(months 0 -7
post -injection)Season 2
(months 8 -14
post -injection )3
Outpatient visits3
Trial efficacy against medically -attended
RSV ARIAges 60 –74 yrs:
79.0%
Ages ≥75 yrs:
39.5%Ages 60 –74 yrs:
27.8%
Ages ≥75 yrs:
13.9%Ages 60 –74 yrs:
65.2%
Ages ≥75 yrs:
32.6%Ages 60 –74 yrs:
55.0%
Ages ≥75 yrs:
27.5%
Hospitalizations, ICU Admissions,
and In -hospital Deaths
Trial efficacy against medically -attended
RSV LRTD/LRTIAges 60 –74 yrs:
87.5%4
Ages ≥75 yrs:
43.8%Ages 60 –74 yrs:
52.9%4
Ages ≥75 yrs:
26.5%Ages 60 –74 yrs:
84.6%5
Ages ≥75 yrs:
42.3%Ages 60 –74 yrs:
75.0%5
Ages ≥75 yrs:
37.5%Inputs: Vaccine Efficacy (VE), sensitivity analysis
13Point estimates were used in this analysis. Uncertainty in vaccine efficacy was not incorporated into uncertainty in estimate d preventable outcomes.
Ref (Slide 18): https://www.cdc.gov/vaccines/acip/meetings/downloads/slides -2023 -06-21-23/05 -RSV -Adults -Ortega -Sanchez -508.pdf
1 GSK Phase 3 Trial; interim analysis 2023; CDC -calculated vaccine efficacy in participants ages ≥60 years
2 Pfizer Phase 3 Trial; interim analysis 2023; CDC -calculated vaccine efficacy in participants ages ≥60 years
3 Efficacy estimates are not directly comparable. Clinical trials used different outcome definitions and the follow up time in differed substantially across trials. Further, efficacy
estimates are associated with substantial uncertainty.
4 CDC -calculated VE against medically -attended RSV acute respiratory illness (ARI)
5 CDC -calculated VE against medically -attended RSV lower respiratory tract disease (LRTD)
6 CDC -calculated VE against medically -attended RSV lower respiratory tract illness (LRTI) with at least 3 lower respiratory sympto ms
Results: Estimated Benefits
Per 1 million vaccine doses administered
Estimated RSV -Associated Outcomes* Preventable over 2 RSV Seasons
per 1 Million Vaccine Doses Administered to Adults Aged ≥60 Years
*Ranges of preventable outcomes were calculated using published 95% confidence intervals (outpatient only) and adjusted 95% confidence interval of
RSV-associated incidence of the outcome observed in RSV -NET. Uncertainty in vaccine efficacy was not incorporated into ranges of preventable outcomes.120 450 2,400
- 1,000 2,000 3,000 4,000 5,000140 520 2,700
- 1,000 2,000 3,000 4,000 5,000Outpatient visits
Hospitalizations
ICU Admissions
In-hospital Deaths//23,000Arexvy (GSK) Abrysvo (Pfizer)
\\26,000
15
Estimated RSV -Associated Outcomes* Preventable over 2 RSV Seasons
per 1 Million Vaccine Doses Administered, Arexvy (GSK)
350 870 6,000
170 660 3,200
86 390 1,900
66 340 1,500
41 260 1,100
- 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,00060-64 years
65-69 years
70-74 years
75-79 years
≥80 yearsHospitalizations
ICU Admissions
In-Hospital Deaths
*Ranges of preventable outcomes were calculated using published 95% confidence intervals (outpatient only) and adjusted 95% confidence interval of
RSV-associated incidence of the outcome observed in RSV -NET. Uncertainty in vaccine efficacy was not incorporated into ranges of preventable outcomes.16
// 18,000
// 24,000
// 24,000
// 24,000
// 24,000
// 23,000
175 435 3,000
85 330 1,600
86 390 1,900
66 340 1,500
41 260 1,100
- 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,00060-64 years
65-69 years
70-74 years
75-79 years
≥80 yearsHospitalizations
ICU Admissions
In-Hospital DeathsSensitivity analysis:
Vaccine efficacy reduced by
half among adults ≥75 yearsEstimated RSV -Associated Outcomes* Preventable over 2 RSV Seasons
per 1 Million Vaccine Doses Administered, Arexvy (GSK)
*Ranges of preventable outcomes were calculated using published 95% confidence intervals (outpatient only) and adjusted 95% confidence interval of
RSV-associated incidence of the outcome observed in RSV -NET. Uncertainty in vaccine efficacy was not incorporated into ranges of preventable outcomes.17
Estimated RSV -Associated Outcomes* Preventable over 2 RSV Seasons
per 1 Million Vaccine Doses Administered, Abrysvo (Pfizer)
Hospitalizations
ICU Admissions
In Hospital Deaths
400 990 6,800
200 750 3,600
98 440 2,200
75 380 1,700
46 300 1,200
0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,00060-64 years
65-69 years
70-74 years
75-79 years
≥80 years
*Ranges of preventable outcomes were calculated using published 95% confidence intervals (outpatient only) and adjusted 95% confidence interval of
RSV-associated incidence of the outcome observed in RSV -NET. Uncertainty in vaccine efficacy was not incorporated into ranges of preventable outcomes.18
Hospitalizations
ICU Admissions
In Hospital Deaths
200 495 3,400
100 375 1,800
98 440 2,200
75 380 1,700
46 300 1,200
0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,00060-64 years
65-69 years
70-74 years
75-79 years
≥80 yearsSensitivity analysis:
Vaccine efficacy reduced by
half among adults ≥75 yearsEstimated RSV -Associated Outcomes* Preventable over 2 RSV Seasons
per 1 Million Vaccine Doses Administered, Abrysvo (Pfizer)
*Ranges of preventable outcomes were calculated using published 95% confidence intervals (outpatient only) and adjusted 95% confidence interval of
RSV-associated incidence of the outcome observed in RSV -NET. Uncertainty in vaccine efficacy was not incorporated into ranges of preventable outcomes.19
▪23,000 (17,000 –28,000)
▪2,400 (1,800 –3,700)
▪450 (350 –690)
▪120 (94 –190)Summary:
Estimated preventable RSV -associated outcomes varies by age and incidence of the outcome
Arexvy (GSK)
▪26,000 (19,000 –32,000)
▪2,700 (2,100 –4,200)
▪520 (400 –780)
▪140 (110 –210)Abrysvo (Pfizer)
Outpatient visits
Hospitalizations
ICU admissions
In-hospital deaths▪Estimated number of outcomes preventable over 2 RSV seasons
per 1 million doses administered were similar between vaccine products:
Ranges of preventable outcomes were calculated using published 95% confidence intervals (outpatient only) and adjusted 95% confidence interval of R SV-
associated incidence of the outcome observed in RSV -NET. Uncertainty in vaccine efficacy was not incorporated into ranges of preventable outcomes.20
Potential Risk of Guillain -Barre syndrome (GBS)
Per 1 million vaccine doses administered
▪Claims -based ascertainment of GBS events using administrative data
–GBS cases observed after RSV vaccination during a 42-day risk interval2, adjusted for delays in claims data
–Adjustment for positive -predictive value of diagnostic codes in identifying chart -confirmed GBS
▪GSK Arexvy : 10 GBS cases (95% CI 2 –18) per 1 million doses administered
▪Pfizer Abrysvo : 25 GBS cases (95% CI 7 –43) per 1 million doses administered
▪Expected cases based on historical GBS background rate from 2022:
–5 GBS cases per 1 million doses administered3
–Historical background rate may not be applicable to persons electing to receive RSV vaccination using
shared clinical decision -making. On average, recipients of each of the two vaccines may be at different
baseline risk of GBS. More robust analysis, such as a self -controlled case series, is needed to confirm and
quantify a risk of Guillain -Barre syndrome after RSV vaccination.FDA active surveillance through partnership with CMS,
Medicare beneficiaries ages ≥65 years1, May –December 2023
Abbreviations: CI = confidence interval, CMS = Centers for Medicare & Medicaid Services, FDA = U.S. Food and Drug Administrat ion, GBS = Guillain -Barre syndrome
1.Must have been enrolled in Medicare Parts A, B and D. Must not have had a diagnostic code for GBS in the 365 days preceding v accination.
2.Due to delays in claims data, not all participants have accrued 42 days of effective follow up time. GBS observation rates pe r 1 million doses over a 21-day risk interval
were also calculated ( GSK Arexvy : 5 cases [95% CI 1 –9], Pfizer Abrysvo : 13 cases [95% CI 3 –22]).
3.The lower and upper bounds of the 95% confidence interval for the expected cases both round to 5. With additional precision: 5.06 expected GBS cases (95% CI 4.76 –
5.38) per 1 million doses administered to adults ages 65 years and older. 22
Estimated Benefits and
Potential Risk
Per 1 million vaccine doses administered
Per 1 Million Vaccine Doses Administered to Adults Aged ≥60 Years:
1.Range of outcomes avertable was calculated using published 95% confidence intervals (outpatient only) and adjusted 95% confid ence interval of RSV -associated incidence of the outcome observed in RSV -NET
2.Includes GBS cases in a 42 -day risk interval post -RSV-vaccination, adjusted for claims delay, a mong beneficiaries ≥65 with Parts A, B, and D coverage who did not have a GBS claim in the 365 days before
vaccination. Rates of GBS identified by inpatient claims data are decreased by 29% to account for the positive predictive val ue of diagnostic codes in identifying chart -confirmed GBS cases.
3.Background GBS rate (4.4 cases per 100,000 person -years) from 2022 CMS data among Medicare beneficiaries 65 years and older with Parts A, B, and D coverage and without a GBS claim in the 365 days
before January 1, 2022. Rates of GBS identified by inpatient claims data are decreased by 29% to account for the positive pre dictive value of diagnostic codes in identifying chart -confirmed GBS cases.Estimated RSV -Associated Outcomes1 Preventable over 2 RSV Seasons vs. potential cases of GBS
(positive predictive value -adjusted rate of GBS claims in FDA -CMS partnership data, 42 -day risk interval2)
By comparison, 5 GBS cases would be expected from background over the 42 -day risk interval3.
Historical background rate may not apply to adults electing to receive RSV vaccination using shared clinical decision -making. On average, recipients of each of the two
vaccines may be at different baseline risk of GBS. More robust analysis, such as a self -controlled case series, is needed to con firm and quantify a risk of GBS.10 (95% CI 2–18) cases of GBS 25 (95% CI 7–43) cases of GBS
1.Range of outcomes avertable was calculated using published 95% confidence intervals (outpatient only) and adjusted 95% confid ence interval of RSV -associated incidence of the outcome observed in RSV -NET
2.Includes GBS cases in a 42 -day risk interval post -RSV-vaccination, adjusted for claims delay, a mong beneficiaries ≥65 with Parts A, B, and D coverage who did not have a GBS claim in the 365 days before
vaccination. Rates of GBS identified by inpatient claims data are decreased by 29% to account for the positive predictive val ue of diagnostic codes in identifying chart -confirmed GBS cases.
3.Background GBS rate (4.4 cases per 100,000 person -years) from 2022 CMS data among Medicare beneficiaries 65 years and older with Parts A, B, and D coverage and without a GBS claim in the 365 days
before January 1, 2022. Rates of GBS identified by inpatient claims data are decreased by 29% to account for the positive pre dictive value of diagnostic codes in identifying chart -confirmed GBS cases.Estimated RSV -Associated Outcomes1 Preventable over 2 RSV Seasons vs. potential cases of GBS
(positive predictive value -adjusted rate of GBS claims in FDA -CMS partnership data, 42 -day risk interval2)
By comparison, 5 GBS cases would be expected from background over the 42 -day risk interval3.
Historical background rate may not apply to adults electing to receive RSV vaccination using shared clinical decision -making. On average, recipients of each of the two
vaccines may be at different baseline risk of GBS. More robust analysis, such as a self -controlled case series, is needed to con firm and quantify a risk of GBS.10 (95% CI 2–18) cases of Guillain -Barre syndromePer 1 Million GSK Arexvy Doses Administered to Older Adults:
60–64 yrs 65–69 yrs 70–74 yrs 75–79 yrs ≥80 yrs
Hospitalizations
preventable1,100 1,500 1,900 3,200 6,000
ICU admissions
preventable260 340 390 660 870
In-hospital deaths
preventable41 66 86 170 350
25
1.Range of outcomes avertable was calculated using published 95% confidence intervals (outpatient only) and adjusted 95% confid ence interval of RSV -associated incidence of the outcome observed in RSV -NET
2.Includes GBS cases in a 42 -day risk interval post -RSV-vaccination, adjusted for claims delay, a mong beneficiaries ≥65 with Parts A, B, and D coverage who did not have a GBS claim in the 365 days before
vaccination. Rates of GBS identified by inpatient claims data are decreased by 29% to account for the positive predictive val ue of diagnostic codes in identifying chart -confirmed GBS cases.
3.Background GBS rate (4.4 cases per 100,000 person -years) from 2022 CMS data among Medicare beneficiaries 65 years and older with Parts A, B, and D coverage and without a GBS claim in the 365 days
before January 1, 2022. Rates of GBS identified by inpatient claims data are decreased by 29% to account for the positive pre dictive value of diagnostic codes in identifying chart -confirmed GBS cases.Estimated RSV -Associated Outcomes1 Preventable over 2 RSV Seasons vs. potential cases of GBS
(positive predictive value -adjusted rate of GBS claims in FDA -CMS partnership data, 42 -day risk interval2)
By comparison, 5 GBS cases would be expected from background over the 42 -day risk interval3.
Historical background rate may not apply to adults electing to receive RSV vaccination using shared clinical decision -making. On average, recipients of each of the two
vaccines may be at different baseline risk of GBS. More robust analysis, such as a self -controlled case series, is needed to con firm and quantify a risk of GBS.25 (95% CI 7–43) cases of Guillain -Barre syndromePer 1 Million Pfizer Abrysvo Doses Administered to Older Adults:
60–64 yrs 65–69 yrs 70–74 yrs 75–79 yrs ≥80 yrs
Hospitalizations
preventable1,200 1,700 2,200 3,600 6,800
ICU admissions
preventable300 380 440 750 990
In-hospital deaths
preventable46 75 98 200 400
26
▪We assumed optimal timing of vaccination immediately before onset of RSV season.
▪We assumed that the real -world vaccine effectiveness is equal to point estimate of vaccine
efficacy observed in the phase 3 clinical trials.
–Assumed vaccine effectiveness against hospitalization was equal to vaccine efficacy against medically
attended RSV -associated lower respiratory tract disease from clinical trials
–Did not incorporate uncertainty in trial efficacy estimates. However, in preliminary analyses, uncertainty
in RSV incidence resulted in wider ranges of preventable outcomes than uncertainty in efficacy.
▪Clinical trials were performed largely in community dwelling older adults and may not be
generalizable to all adults 60+ in the U.S.
▪RSV -NET represents ~9% of the United States and hospitalization rates observed in RSV -NET
may not be generalizable to the U.S.
▪Benefits of a single dose of RSV vaccination may continue to accrue beyond 2 years.
▪RSV -NET does not currently estimate out -of-hospital deaths, resulting in an under -estimate of
potentially vaccine -preventable deaths.
▪Benefits may be greater for subgroups of adults at increased risk of severe RSV illness.Limitations (estimation of benefits)
27
▪GBS rates were calculated using a small number of events observed after RSV
vaccination, resulting in high uncertainty.
▪A background rate of GBS was not subtracted from the observed rate.
–The historical background rate from CMS used as a comparator may not apply to adults receiving RSV
vaccination using shared clinical decision -making; subject to confounding and bias.
▪Older adults receiving each of the two vaccine products may have different prevalence
of chronic medical conditions or other risk factors and may therefore have different
baseline risk of GBS.
▪GBS was identified by diagnostic codes in administrative data and may be subject to
coding errors.
▪Not all cases of GBS occurring after RSV vaccination may have received a diagnostic
code.Limitations (estimation of risk)
28
▪From a population perspective, the estimated benefits of RSV vaccination outweigh
the potential risk of GBS in adults 60 years and older.
▪Estimated benefits of RSV vaccination vary by age group and RSV incidence.
▪Estimated benefits likely also vary by individual -level risk of severe RSV disease and by
timing of vaccination relative to the RSV season.
▪There is substantial uncertainty in estimates of both benefit and risk.
▪The benefit and risk assessment will be updated as additional data become available:
–Results from additional vaccine safety studies
–Additional efficacy follow -up time from clinical trials
–Vaccine effectiveness from post -licensure observational studies, including effectiveness against more
severe clinical outcomes
–RSV disease burden among subgroups of older adults at increased risk of severe RSV diseaseSummary
29
▪Lauren Roper
▪Amadea Britton
▪Dani Moulia
▪Megan Wallace
▪Katherine Fleming -Dutra
▪Fiona Havers
▪Michael Whitaker
▪John Su
▪Karen Broder▪Eric Weintraub
▪David Shay
▪Anne Hause
▪Pedro Moro
▪Tom Shimabukuro
▪Patricia Lloyd
▪Richard Forshee
▪Steven AndersonAcknowledgements
30
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1-800 -CDC -INFO (232 -4636)
TTY: 1 -888 -232-6348 www.cdc.gov
The findings and conclusions in this report are those of the authors and do not necessarily represent the official
position of the Centers for Disease Control and Prevention.
Photographs and images included in this presentation are licensed solely for CDC/NCIRD online and presentation
use. No rights are implied or extended for use in printing or any use by other CDC CIOs or any external audiences.