Economics of Preventing Respiratory Syncytial 

Virus Disease among US Infants by Maternal 

Vaccination Prior to Birth

A SUMMARY REPORT COMPARING MODELS FROM:

Pfizer AND University of Michigan and CDC

Ismael R. Ortega-Sanchez, PhD

NCIRD/CDC

ACIP Meeting, September 22, 2023

1

Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of 

the Centers for Disease Control and Prevention. 

National Center for Immunization & Respiratory Diseases
Conflict of interest

• Pfizer model: Amy Law et al., [complete authors list and affiliations, upon 

request ]

• Pfizer manufactures RSVpreF vaccine

• Policy Analysis Inc. (Boston, MA, US) was funded by Pfizer

• UM-CDC model: David W Hutton et al. from University of Michigan, 

Ismael R Ortega-Sanchez et al. from CDC [complete authors list and affiliations, 

upon request ]

• All authors: No conflicts of interest

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Economic analysis

Policy question: Should Pfizer RSVpreF vaccine be recommended for pregnant mothers to be given 

during 32 through 36 weeks gestation to prevent RSV lower respiratory tract infection in infants?

Question: Is vaccinating pregnant mothers prior to birth to protect infants against RSV disease costeffective?

Comparator Intervention

Base-case scenario: What is the incremental cost-effectiveness of vaccinating pregnant mothers 32-36wGA and 

≥2 weeks prior to birth with RSVPreF vaccine relative to “No vaccination”?

3

Unvaccinated 

Mothers +

Standard of care (SoC)

for Infants

Vaccination of 

pregnant mothers 

prior to birth

Standard of Care (SoC) = Palivizumab only for infants eligible as per AAP recommendations, and no immunization for all other pre-term and full term infants
Focus on key features for model comparison

• Modeling approach

• Targeted population(s)

• Perspective (healthcare vs. societal)

• Intervention strategies and comparators

• Inputs for RSV disease burden, vaccine efficacy, and costs

• Incidence of RSV disease, rates of outcomes 

• Direct and indirect costs of RSV disease

• Intervention: efficacy, duration of protection, safety and program costs

• Assumptions

• Strong, influential assumptions

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5

Modeling design and assumptions

Pfizer UM-CDC

Static analytical decision-making models ✔ ✔

Sensitivity analyses (and probabilistic simulation) ✔(✔) ✔

Hypothetical population: All pregnant mothers, all year round ✔ ✔

Time Frame: First year after birth ✔ ✔

Analytic Horizon: One year (for temporary disability) and Life 

Expectancy (for premature infant mortality)

✔

✔

✔

✔

Discount rate: 3% ✔ ✔

Year of economic outcomes measured: 2022 ✔ ✔

Societal perspective (and healthcare perspective) ✔(✔) ✔(✔)
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Inputs and main outcomes

Prevention of:

• RSV LRTI ED/OC visits

• RSV LRTI hospitalizations

• RSV-associated deaths

QALYs saved

$/QALY saved

Number needed to

vaccinate (NNV) to avert an:

• RSV LRTI hospitalization

• RSV-associated death

Pfizer UM-CDC

✔ ✔

✔ ✔

✔ ✔

✔ ✔

✔ ✔

✔ ✔

✔ ✔

HCRU = health care resource use, ED= Emergency department, OC= outpatient clinic, LRTI= Lower respiratory tract infection, 

QALY= quality-adjusted life year
$11 

$33 

$68 

$311 

$13 

$104 

 $-

 $50

 $100

 $150

 $200

 $250

 $300

 $350

Outpatient ED Inpatient ICU Inpatient

Day

ICU Day

Cost per Event Averted (thousands)

UM-CDC: Base case estimates for maternal vaccination, 

Vaccination Window (VW) 32-36wGA, vaccine cost $295/dose

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Cost per type of health outcome prevented (in thousands) 

Summary outcomes Base-Case

$/QALY gained $400,304

$/RSV-associated ED/OC visit 

averted $32,652 / $11,337 

$/RSV-associated 

LRTI hospitalization averted $68,423

$/RSV-assoc. death averted >$71.5Million

NNV to avert an RSV-associated 

ED/ OC patient 115 / 40 

NNV to avert an RSV-associated 

LRTI hospitalization 242

NNV to avert an RSV-associated 

death 241,989

Assuming 50% uptake in vaccinated group

VW = vaccination window

wGA = weeks gestational age

LRTI= lower respiratory tract infection

OC = office clinic for outpatient care

ED = emergency department

NNV = Number needed to vaccinate
Pfizer model: Base case estimates for maternal vaccination, 

VW 32-36wGA, vaccine cost $295/dose & PSA

8

Summary outcomes Base-Case

$/QALY gained $84,690

$/RSV-associated ED/OC visit 

averted $6,145/ $2,101

$/RSV-associated LRTI 

hospitalization averted $14,932

$/RSV-associated death averted >$7.7Million

NNV to avert an RSV-associated 

ED/OC patient 66 / 22

NNV to avert an RSV-associated 

LRTI hospitalization 159

NNV to avert an RSV-associated 

death 82,243

Probabilistic sensitivity analysis (PSA)

87.1%

65.1%

34.7%

Difference in total QALYs

Difference in total costs (in millions)

Assuming 54.9% uptake in vaccinated group and 93.2% born ≥2 weeks after adm. Base-case

VW = vaccination window

wGA = weeks gestational age

LRTI= lower respiratory tract infection

OC = office clinic

ED = emergency department

NNV = Number needed to vaccinate

WTP = Willingness to pay
Pfizer and UM-CDC models comparison: base-case

selected outcome ratios for maternal vaccination

9

UM-CDC model

Price per dose $295

VW=32-36wGA

Year-round 

administration

Pfizer model

Price per dose $295

VW=32-36wGA

Year-round

administration

$ / QALY gained $400,304 $84,690

$ / RSV LRTI hospitalization averted $68,423 $14,932

$ / Death averted among RSV LRTI hospitalized infants >$71.5Million >$7.7Million

NNV to prevent a

RSV LRTI associated hospitalization 242 159

Death among RSV LRTI hospitalized infants 241,989 82,243

Assuming 50% (UM-CDC) and 54.9% (Pfizer) uptake in vaccinated group and 100% (UM-CDC) to 93.2% (Pfizer) born ≥2 weeks after administration.

VW = Vaccination window

LRTI= lower respiratory tract infection

NNV = Number needed to vaccinate

Note: Both models vaccination window = 32-36wGA only (wGA = weeks gestational age)
$0 $100 $200 $300 $400 $500 $600 $700 $800

Probability of Prematurity

RSV QALYS Lost

RSVpreF vaccine cost/dose

Disease-specific inpatient costs (per inpatient case)

Vaccination Efficacy, Hospitalized RSV LRTI through 180 days

RSV-related QALYs lost Outpatient Child

Vaccination Efficacy, RSV MA-LRTI through 180 days

Proportion of RSV infections with an LRTI diagnosis...

RSV-related QALYs lost Outpatient Caregiver

RSV-related QALYs lost ED Child

Incremental Cost-Effectiveness Ratio (in thousands)

Low

High

UM-CDC model: One-way Sensitivity Analyses 

Base case: $400,304/QALY saved, vaccine price $295/dose

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MA= Medically-attended

LRTI= Lower respiratory tract infection

QALY= Quality adjusted life year

$1.3 

Million

Base-case $400,304
Pfizer model: One-way Sensitivity Analyses 

Base case: $84,690/QALY saved, Vaccine cost $295/dose

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CFR= Case fatality ratio

DoP = Duration of protection

VE= Vaccine efficacy

PT = Preterm

FT = Full term

RSV-H = RSV-associated hospitalization

RSV-ED = RSV-associated emergency department care

RSV-OC = RSV-associated outpatient care

15) VE lower bound

14) RSV-H medical care cost lower bound

13) US healthcare system perspective

12) DoP = 6 months

11) RSV-H CFR lower bound (overall = 0.1%)

10) Vaccine uptake 32-36 wGA (uniform)

9) Disutilities form Glasser (RSV-H) and 

Reigner (RSV-ED, RSV-OC)

8) Uptake = 100%

7) Base case

6) VE for late PT = for FT

5) Palivizumab scenario

4) DoP = 12 months

3) RSV-H CFR upper bound (overall=0.53%)

2) RSV-H medical care cost upper bound

1) VE upper bound

Base-case $84,690

Sensitivity / Scenario Analysis

Cost per QALY
Pfizer and UM-CDC models comparison: 

Selected influential inputs 

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• RSV-hospitalization risk and RSV seasonality

• Vaccine efficacy

• Duration of protection and waning

• RSV Case fatality rate

• Medical cost of RSV hospitalization, ED and Outpatient care

• Vaccine associated adverse events

• Quality of life lost by patients and caregivers
Pfizer and UM-CDC: comparison of base-case risk of 

RSV-related hospitalization by age and RSV Seasonality 

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Risk of RSV Hospitalization: Pfizer and UM-CDC: Based on laboratory-confirmed RSV-associated hospitalization by age in months from New Vaccine Surveillance 

Network (NVSN) data for children under 2 years of age (December 2016 to September 2020). Risk estimates are based only on RSV cases that manifest as LRTI.

RSV Seasonality: Pfizer: based on Midgley et al. J Infect Dis 2017. (data based in NRVSS) https://pubmed.ncbi.nlm.nih.gov/28859428/#full-view-affiliation-1

UM-CDC: based on National Respiratory and Enteric Virus Surveillance System (NREVSS) (2015-2019)

0%

5%

10%

15%

20%

25%

30%

Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar

Fraction of Annual Infections 

Pfizer

UM-CDC

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0 1 2 3 4 5 6 7 8 9 10 11

Risk of RSV LRTI hospitalization

Age (in months)
Pfizer and UM-CDC: Differences in initial vaccine 

efficacy

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NOTE: None of Pfizer Phase 3 (i.e., MATISSE) endpoint definitions overlapped ideally with the case definition used for the US burden data.

a. CDC: Average between efficacy for full term and preterm reported from Phase 3 were used. VE for RSV-LRTI hospitalization is an average over months 0-6 reported 

in Phase 3 trial, and RSV-positive MA-LRTI for VE against RSV-LRTI in the ED and outpatient. Kampmann et al New England Journal of Medicine. 2023 Apr

b. Pfizer: Efficacy against severe RSV-positive MA-LRTI was used as a proxy for VE against RSV-LRTI requiring hospitalization, and efficacy against RSV-positive MA-LRTI 

was used as a proxy for VE against RSV-LRTI treated in the ED. Pfizer: Kampmann et al New England Journal of Medicine. 2023 Apr

c. VE for late preterm infants was assumed to be 83.3% of corresponding values for full term infants. VE for URTI was assumed equal to VE for MA LRTI in ED care

d. Based on overall respiratory tract efficacy from phase 3 trial (Kampmann et al New England Journal of Medicine. 2023 Apr )

UM-CDC Pfizer

Full Term Late Preterm

Initial vaccine efficacy against

RSV LRTI hospitalization (%)

Month 0 = 81.0

Average Month 0-6 = 56.8 a

88.1

Severe MA

RSV-LTRI b

73.4

Severe MA

RSV-LRTI b, c

Initial vaccine efficacy against

Medically attended RSV associated LRTI for ED 

and Outpatient care (%)

Month 0 = 73.0

Average Month 0-6 = 51.3 a

47.6 b 39.7 c

For Scenario Analysis only: Initial efficacy 

against RSV URTI treated in Outpatient care (%) 37.9 d 47.6 b 39.7 c
0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 3 6 9 12

Efficacy

Month

Against medically-attended RSV-associated LRTI

Against hospitalization

average 6-month efficacy = 

efficacy against hospitalization 

or medically-attended RSVassociated LRTI

Zero 

efficacy

The pink-shaded areas denote a higher level of uncertainty of the waning assumption beyond available phase 3 data

UM-CDC: Average between efficacy for full term and preterm were used for DoP for RSV-LRTI hospitalization over months 0-6 and RSV-positive MA-LRTI for DoP

against RSV-LRTI in the ED and outpatient also over months 0-6. Both reported in Phase 3 trial, Kampmann et al New England Journal of Medicine. 2023 Apr

Pfizer and UM-CDC: Assumption on duration of 

protection (DoP)

15

Pfizer UM-CDC

VE against ED or OC VE against hospitalization

4 trial 

endpoints

81.0

73.0
16

UM-CDC Pfizer

Case fatality rate (CFR) among RSVhospitalized infants <12 months of age

0.10%

(0.04% - 0.20%)a

0.10% (full term)

0.80% (all preterm) b

Medical costs per RSV hospitalization $11,487

($4,804 - $86,646)c

Average: $20,483 d

$13,171 – $33,876 (full term)

$19, 415 – $51,343 (late preterm)

Medical costs per RSV ED visit $563

($544 -$581)c

Average: $1,840 d

$1,620 – $2,520 (full term)

$1,787 – $2,779 (late preterm)

Medical costs per RSV outpatient visit $82

($46 - $118)c

Average: $348 d

$292 – $730 (full term)

$328 – $823 (late preterm)

a. RSV mortality per hospitalization: 0.10% (range 0.04-0.20%) in 0-5months, 0.10% (range 0.04-0.20%) in 6-11months.

b. Case fatality due to RSV-Hospital in full term infants per 100 cases = 0.1 (based on Li et al CEA-RSV in children 2022). In pre-term infants CFR per 100= 0.8 (assumes 16.3% of all RSV-Hosp 

are among preterm) 

c. Adapted from Bowser et al., J Infect Dis. 2022 Aug 15; 226(Suppl 2): S225–S235 (A systematic review using studies from 2014-2021. Cost updated to 2022 using the GPD deflator)

d. Source: Pfizer data on file. Costs in the base-case varied by age and term at birth. Weighted average cost among full and late preterm infants in commercially insured and Medicaid 

populations

Pfizer and UM-CDC models comparison: 

Differences in key inputs
Pfizer and UM-CDC: Vaccine-associated adverse 

events 

17

UM-CDC Pfizer Source

Rate of injection site reaction 0.41

(0.38 – 0.44)

0.41

(0.38 – 0.44} Pfizer Phase III Trial

Probability of healthcare visit, given 

injection site reaction

0.02

(0.015 – 0.025)

0.02

(0.015 – 0.025)

Curran, 2020

Cost of outpatient visit $367.76

(23.15 – 1,758)

$367.76

(23.15 – 1,758)

(Deluca, 2023) also in Pfizer CEA 

technical report (August 2023)

Recipient time, physician office for 

injection site reaction (hours)

2

(1 – 3)

n/r Assumption

Hypothetical serious adverse event 0.000001

( 0 - 0.0002)

n/r

Base: Prosser, 2006

High: 95% CI Phase 3 data for 

RSV adult vaccines

Potential risk increase of prematurity 0.0%

( 0 – 2%)

n/r

Pfizer Phase III Trial

Kampmann et al New England 

Journal of Medicine. 2023 Apr

Note: Values in bold are used for the base-case scenario. Range values in parenthesis for sensitivity analyses

n/r = not reported
Pfizer and UM-CDC: Quality of life lost (in days) 

by RSV LRTI outcome for patients & caregivers

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UM-CDC* Pfizer**

Outpatient: Child 3.1

(1.8 - 16.6)

2.22

Outpatient: Caregiver 1.5

(0 - 9.1) 1.5

ED: Child 4.9

(2.9 – 16.6) 2.22

ED: Caregiver 2.5

(0 - 9.1) 2.5

Hospitalized: Child 6.2

(3.7 – 26.5) 5.7

Hospitalized: Caregiver 2.4

(0 – 13.6) 2.4

Scenario Analysis: Vaccine-related increased 

risk of prematurity ***

11

(0 – 438) n/r

* Base case values are from EGlasser et al 2022, lower values are based in Regnier et al 2013, higher values are based in JIVE (unpublished data)

** Patient values are base in Roy 2013, Caregiver values are based on Hutton. Economic Analysis of Nirsevimab in Pediatric Populations. ACIP; February 23, 2023.

Note: Values in bold are used for the base-case scenario. Range values in parenthesis for sensitivity analyses

*** Sources: Werner, et al 2015. Petrini et al, 2008, Hirvonen et al, 2014, Crump et al, 2021, Darcy-Mahoney et al, 2016, Carroll et al, 2009, Payakachat et al, 2014

n/r = not reported
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UM-CDC

UM-CDC model Base-case $400,304

A Cost of RSV-LRTI hospitalization: $20,000 or $50,000 (i.e., 85% to 450% increase, base-case 

cost= $11,487) $350,500 - $174,987

B UM-CDC model with same VE duration of protection as Pfizer: 6 months slowly, linearly 

declining efficacy and declining faster after month 6 reaching 0% at month 9 $286,769

C CFR among RSV LRTI hospitalization: 1% (base-case = 0.1%) $122,539

D Combining A and B vs. Combining A, B and C $233,736 - $52,108

E Increase in the risk of prematurity in one- or two-percent points (base-case risk of prematurity 

after vaccination = 0% increase ) $874,609 - $1.3 Million

F Vaccine administration timing: September-January vs. February-July (base-case, year-round) <$200,000 - $Millions

G Vaccine cost = $50/dose or $500/dose (base-case vaccine cost = $295/dose) $65,304 - $680,609

H VE for URTI = 37.9% (Base-case = 0% VE against URTI) $279,490

Pfizer and UM-CDC models comparison: 

$/QALY for selected scenarios in UM-CDC model
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Pfizer

Pfizer model base-case $84,690

VE for late preterm infants assumed same as for full term infants a

$73,404

Vaccine Efficacy: 80% or 120% of base case values $155,834 - $43,813

Trial-based VE over 6 months, then 0% VE or linear waning to 0% VE at 12 months $111,473 - $61,925

Overall CFR among RSV hospitalized: 0.1% or 0.53% b

$102,431 - $52,000

Costs of RSV-Hospitalization 80% or 120% of base-case) $118,625 - $50,755

Vaccination window: 32-36 wGA only (uniform: 20% in each week) c

$91,036

Maternal vaccine and palivizumab in <1y infants vs. palivizumab only for prevention of RSV $66,796

a. Base-case assumes for late pre-term a VE =83% of the VE for full term (VE = Vaccine efficacy)

b. CFR among RSV hospitalized: 0.1% (RR of RSV-H death = 1 for full term and preterm infants). For CFR 0.53% (using CFR values from full term = 0.3% and preterm = 1.7%) 

c. wGA = weeks gestational age 

Pfizer and UM-CDC models comparison: 

$/QALY for selected scenarios in Pfizer model (I)
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Pfizer

A Pfizer model with selected UM-CDC Inputs $343,000

B Pfizer model with selected UM-CDC Inputs except for Pfizer initial VE 

assumptions $265,000

C Pfizer model with selected UM-CDC Inputs except for Pfizer initial VE 

assumptions and Pfizer DoP $173,000

D Pfizer model with selected UM-CDC Inputs except for Pfizer initial VE 

assumptions, Pfizer DoP and Pfizer Medical costs $83,000

E Pfizer model with selected UM-CDC Inputs except for Pfizer initial VE 

assumptions, Pfizer DoP, Pfizer Medical costs and Palivizumab use $67,000

DoP = Duration of protection

VE = vaccine efficacy

Pfizer and UM-CDC models comparison: 

$/QALY for selected scenarios in Pfizer model (II)
Limitations

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• Factors not considered that may result in overestimating the ICER 

(underestimating the cost-effectiveness) of maternal vaccination

• In base-case: both models assumed 

• No protection against URTI

• No benefits of vaccination for vaccinated pregnant women

• No out-of-pocket cost accrued by caregivers during infants RSV illness

• Neither model included RSV-related costs incurred after discharge from an 

RSV-associated hospitalization or emergency department visit:

• Productivity losses incurred by caregivers after discharge

• Both models assumed no indirect effects of vaccination (i.e., no protection 

against RSV transmission)
Conclusion

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• Differences in key inputs among Pfizer and UM-CDC models explain differences in results:

• Initial vaccine efficacy and assumptions about protection waning

• Medical costs

• Quality of life associated with RSV LRTI outcomes for patient and caregivers

• Vaccine related adverse events

• In addition, the UM-CDC also identified two important factors that could drive the results

• Hypothetically severe vaccine-associated adverse events

• Timing of vaccination to RSV season

• Base-case in both models:

• Maternal vaccination would significantly reduce RSV disease burden and costs in infants

• Data from clinical trials used in both models support the reduction in RSV disease and 

associated costs

• Economic value of vaccinating pregnant people to protect infants could increase costs

• Reasonable vaccine price and duration of protection combined with careful design of 

seasonal interventions would determine the cost-effectiveness value of routine 

vaccination of pregnant people during the 32-36wGA
Acknowledgements 

From NCIRD/CDC

• Jefferson Jones

• Mila M. Prill

• Katherine E. Fleming-Dutra

• Jamison Pike

• Andrew Leidner

• Meredith McMorrow

Also:

• Maternal/Pediatric RSV working group members

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End of Summary