1

Centers for Disease Control and Prevention

National Center for Immunization and Respiratory Diseases

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.

Proposed clinical considerations for maternal RSVPreF

vaccine and nirsevimab

Jefferson Jones MD MPH FAAP

CDR USPHS

Co-Lead, Respiratory Syncytial Virus Vaccines - Pediatric/Maternal Work Group

Coronavirus and Other Respiratory Viruses Division

National Center for Immunization and Respiratory Diseases

September 22, 2023
2

Proposed clinical considerations 

for use of maternal RSV vaccine
3

▪ Maternal vaccine recommended for pregnant people during 32 through 36 

weeks gestation, with seasonal administration

– During September through January in most of the continental United States

– In jurisdictions with seasonality that differs from most of the continental United 

States (e.g., Alaska, jurisdictions with tropical climates), providers should follow 

state, local, or territorial guidance on timing of administration

▪ Maternal RSVpreF vaccine may be simultaneously administered with 

other indicated vaccinations 1

Proposed clinical considerations for use of maternal RSV 

vaccine

1 https://www.cdc.gov/vaccines/hcp/acip-recs/general-recs/index.html. 
Work Group considerations for 

use of both maternal RSV 

vaccine and nirsevimab
5

▪ As proposed, maternal RSV vaccine recommendation is for administration 

beginning at 32 weeks gestation

▪ From time of maternal vaccination, 14 days or more likely needed for 

development and transplacental transfer of maternal antibodies to 

protect the infant,1 and nirsevimab is recommended for infants born 

within 14 days of vaccination

▪ Therefore, the earliest an infant can be born and have maternal vaccineinduced protection is at 34 weeks gestation

▪ Infants born <34 weeks gestation will be recommended to receive 

nirsevimab

Maternal vaccination and considerations for use of 

nirsevimab in infants born <34 weeks gestation

1 https://www.cdc.gov/vaccines/pregnancy/vacc-during-after.html. 
6

▪ Protection from maternal vaccination may begin to wane after 3 or more 

months (e.g., influenza and COVID-19 vaccines) 1–3

– Work Group members initially concerned that , with a year-round recommendation, infants born prior to the RSV 

season and born to vaccinated mothers would require nirsevimab to boost protection when entering RSV season

▪ However, because maternal RSV vaccine administration is recommended 

during September through January, most infants of vaccinated mothers 

will be born during RSV season (i.e., born during October–March)

▪ Mothers of most infants born outside of RSV season (i.e., born during April 

through September) will not have been vaccinated, and nirsevimab will be 

recommended for these infants

Maternal vaccination and considerations for use of 

nirsevimab in infants born outside of the RSV season

1 Kampmann NEJM 2023. 2 Nunes F1000Res 2018. 3 Zerbo Nat Commun 2023. 
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▪ Two products are available to protect infants from RSV lower respiratory tract 

infection

▪ For infants born to vaccinated mothers, the addition of nirsevimab may 

provide incremental protection, but this is unknown

– No safety data on use of nirsevimab in infants born to vaccinated mothers, but nirsevimab trials 

included infants with maternal infection-induced antibodies and risk likely minimal

▪ For most infants, administering both products is not needed and would not be 

a reasonable and efficient allocation of resources

▪ Documentation of maternal vaccination status may not be available to the 

infant's healthcare provider

Work Group considerations for use of both maternal RSV 

vaccine and nirsevimab
8

▪ Most Work Group members felt that pregnant people should be aware that 

both maternal vaccination and nirsevimab are options when deciding whether 

to be vaccinated

– However, healthcare providers of pregnant people may not have time or feel 

equipped to discuss nirsevimab when counselling

▪ In rare situations flexibility is needed for providers to be able to provide 

nirsevimab when clinically warranted to infants born to vaccinated mothers

– Conditions in pregnant people resulting in an inadequate immune response to vaccine or decrease 

in transplacental antibody transfer1

– Infants who have undergone cardiopulmonary bypass, leading to loss of maternal antibodies2

– Infants with sufficiently increased risk for severe disease to warrant nirsevimab because of the 

potential increased benefit

Work Group considerations for use of both maternal RSV 

vaccine and nirsevimab (cont)

1 Palmerira Clin Dev Immunol 2012. 2 Feltes J Pediatr 2003. 
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Proposed clinical considerations for use 

of maternal RSV vaccine and 

nirsevimab
10

▪ Either maternal vaccination or use of nirsevimab in the infant is 

recommended to prevent RSV lower respiratory tract infection, but 

administration of both products is not needed for most infants

▪ Healthcare providers of pregnant people should provide 

information on both products and consider patient preferences when 

determining whether to vaccinate the pregnant patient or to not 

vaccinate and rely on administration of nirsevimab to the infant after birth

Proposed clinical considerations for maternal RSV vaccine 

and nirsevimab
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Relative risks and benefits of maternal vaccination and 

nirsevimab

Maternal RSV vaccine

Benefits

• Provides protection immediately after 

birth

• May be more resistant to virus mutation

• Avoids injection of infant

Risks

• Protection reduced if fewer antibodies 

produced or are transferred from mother 

to baby (e.g., mother 

immunocompromised or infant born soon 

after vaccination)

• Potential risk of preterm birth

Nirsevimab

Benefits

• Studies of antibody levels suggest that 

protection might wane more slowly

• Can provide antibodies directly if infant 

receives less antibodies from mother

• No risk of adverse pregnancy outcomes

Risks

• Potentially limited availability during 

2023-2024 RSV season

Both products are safe and effective in preventing RSV lower respiratory infection in infants
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▪ Nirsevimab is recommended for infants aged <8 months born 

during or entering their first RSV season if

– Mother did not receive RSV vaccine or unknown if mother received RSV vaccine

– Mother vaccinated but infant born <14 days after vaccination

▪ Nirsevimab is not needed for most infants born ≥14 days after 

maternal vaccination

Proposed recommendations for use of nirsevimab in setting of 

an available maternal RSV vaccine
13

▪ Nirsevimab can be considered in rare circumstances when, per the 

clinical judgment of the healthcare provider, the potential 

incremental benefit of administration is warranted

– Infants born to pregnant people who may not mount an adequate immune response 

to vaccination (e.g., people with immunocompromising conditions) or have 

conditions associated with reduced transplacental antibody transfer (e.g., people 

living with HIV infection)1

– Infants who have undergone cardiopulmonary bypass, leading to loss of maternal 

antibodies2

– Infants with substantial increased risk for severe RSV disease (e.g., 

hemodynamically significant congenital heart disease, intensive care admission and 

requiring oxygen at discharge)

Circumstances for which nirsevimab can be considered when 

mother has received RSV vaccine ≥14 days prior to birth

1 Palmerira Clin Dev Immunol 2012.2 Feltes J Pediatr 2003.
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Nirsevimab administration algorithm for children aged <8 months 

on the day of administration

Nirsevimab 

not needed

No

Any criteria not met

Meet all 3 following criteria? (yes/no)

1. Either mother did not receive RSV vaccine during pregnancy ≥14 

days prior to birth or maternal RSV vaccine status unknown 1

2. Day of nirsevimab administration during October through March 2

3. Never previously received dose of nirsevimab3

Nirsevimab 

recommended

Yes

All 3 criteria met 
15

Nirsevimab administration algorithm for children aged 

<8 months on the day of administration footnotes

1For most infants age <8 months whose mother received RSV vaccine 14 or more days prior to birth, 

nirsevimab is not needed. Nirsevimab can be considered in rare circumstances when, per the clinical 

judgment of the healthcare provider, the potential incremental benefit of administration is warranted. 

These situations include infants born to pregnant people who may not mount an adequate immune 

response to vaccination (e.g., people with immunocompromising conditions) or have conditions associated 

with reduced transplacental antibody transfer (e.g., people living with HIV infection), infants who have 

undergone cardiopulmonary bypass leading to loss of maternal antibodies, and infants with substantial 

increased risk for severe RSV disease (e.g., hemodynamically significant congenital heart disease, intensive 

care admission and requiring oxygen at discharge).

2While the timing of the onset and duration of RSV season may vary, nirsevimab may be administered 

October through the end of March in the majority of the continental United States. Providers may adjust 

timing of administration based on guidance from public health authorities (e.g., CDC, health departments) 

or regional medical centers. Although optimal timing of administration is just before the start of the RSV 

season, nirsevimab may also be administered during the RSV season to infants and children who are ageeligible. Infants born shortly before or during RSV season should receive nirsevimab within one week of 

birth. Nirsevimab administration can occur during the birth hospitalization or in the outpatient setting. 

Infants with prolonged birth hospitalizations related to prematurity or other causes should receive 

nirsevimab shortly before or promptly after hospital discharge.
16

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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.
17

Nirsevimab administration algorithm for children aged 8 through 

19 months on day of administration1

No

Not all 3 criteria met

Meet all 3 following criteria? (yes/no)

1. Child at increased risk for RSV disease2

2. Day of administration during October through March3

3. Has not received 1 dose of nirsevimab during current 

RSV season and has not received 2 total doses4

Nirsevimab 

recommended

Nirsevimab not 

needed

Yes

All 3 criteria met 
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Nirsevimab administration algorithm for children aged 8 through 19 months on day of administration 

footnotes

1Children at increased risk for severe disease aged <8 months of age and entering their second RSV season 

should receive nirsevimab. For example, a child born in March should receive their first RSV dose shortly 

after birth; they may be entering their second RSV season at 7 months of age in October and should not wait 

until 8 months of age to receive nirsevimab. 

2Children aged 8–19 months recommended to receive nirsevimab during their second RSV season by ACIP: 

-Children with chronic lung disease of prematurity who required medical support (chronic corticosteroid 

therapy, diuretic therapy, or supplemental oxygen) any time during the 6-month period before the start of 

the second RSV season

-Children with severe immunocompromise

-Children with cystic fibrosis who have either 1) manifestations of severe lung disease (previous 

hospitalization for pulmonary exacerbation in the first year of life or abnormalities on chest imaging that 

persist when stable) or 2) weight-for-length <10th percentile

-American Indian and Alaska Native children
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Nirsevimab administration algorithm for children aged 8 through 19 months on day of administration 

footnotes

3While the timing of the onset and duration of RSV season may vary, nirsevimab may be administered 

October through the end of March in the majority of the continental United States. Providers may adjust 

timing of administration based on guidance from public health authorities (e.g., CDC, health departments) 

or regional medical centers. Although optimal timing of administration is just before the start of the RSV 

season, nirsevimab may also be administered during the RSV season to infants and children who are ageeligible. Infants born shortly before or during RSV season should receive nirsevimab within one week of 

birth. Nirsevimab administration can occur during the birth hospitalization or in the outpatient setting. 

Infants with prolonged birth hospitalizations related to prematurity or other causes should receive 

nirsevimab shortly before or promptly after hospital discharge.

4Children at increased risk for severe disease should not receive more than two doses of nirsevimab (one 

dose [50mg or 100 mg depending on weight] for the first RSV season and one dose [two 100 mg injections] 

for the second RSV season). Only one dose of nirsevimab is recommended per season (with exception for 

children who undergo cardiac surgery with cardiopulmonary bypass). Nirsevimab is recommended for 

children at increased risk for severe disease (as defined in footnote 4) during their first RSV season, including 

if aged 8-11 months if the child has not received nirsevimab during that RSV season.