Respiratory Syncytial Virus vaccines (RSV)

Options for Infant RSV Prevention

At-a-Glance

Two immunization products are available for the prevention of severe Respiratory Syncytial Virus (RSV) disease in 

infants: maternal RSV vaccine and infant RSV monoclonal antibody. All infants should be protected against severe 

RSV disease through use of one of these products. 

Either maternal RSV vaccination or use of RSV monoclonal antibody in the infant is recommended. 

Administration of both products is not needed for most infants.

Maternal RSV vaccination: Use ONLY Pfizer RSVPreF vaccine (trade name AbrysvoTM)

Maternal RSV Vaccine

RSVPreF vaccine (trade name AbrysvoTM) is recommended for people during weeks 32 through 36 of pregnancy, using 

seasonal administration, to prevent severe RSV disease in infants. In clinical trials, there was a small increase in the 

number of preterm birth events in vaccinated pregnant people after vaccination. It is not clear if this is a true safety 

problem related to RSV vaccine or if this occurred for reasons unrelated to vaccination.

Infant RSV Monoclonal Antibody*

RSV monoclonal antibody (generic name nirsevimab, trade name BeyfortusTM) is recommended for the following:

• Infants less than 8 months of age born during or entering their first RSV season if: 

o Mother did not receive maternal RSV vaccine or it is unknown if mother received RSV vaccine 

OR

o Infant was born less than 14 days after maternal RSV vaccination†

In rare circumstances, nirsevimab may be considered for infants born to mothers vaccinated 14 or more days before birth 

when the health care provider believes the potential incremental benefit is warranted. These situations include, but are 

not limited to:

o Infants born to mothers who might not have mounted an adequate immune response to vaccination (e.g., people with 

immunocompromising conditions) 

o Infants born to mothers who have conditions associated with reduced transplacental antibody transfer (e.g., people living 

with HIV infection)

o Infants who might have experienced loss of maternal antibodies, such as those who have undergone cardiopulmonary 

bypass of extracorporeal membrane oxygenation (ECMO)

o Infants with substantial increased risk for severe RSV disease (e.g., hemodynamically significant congenital heart disease, 

intensive care admission with the requirement for oxygen at hospital discharge)

• Some infants and children aged 8 through 19 months who are at increased risk of severe RSV disease entering 

their second RSV season.

o American Indian/Alaska Native children

o Children with chronic lung disease of prematurity who require medical support during the six months before the start of 

their second RSV season

o Children with severe immunocompromise

o Children with severe cystic fibrosis

*Note: A different monoclonal antibody, palivizumab, is used in children under 24 months of age with certain conditions that place them at high risk for severe 

RSV disease. Please see AAP guidelines for palivizumab. AAP has published considerations on the use of nirsevimab and palivizumab: https://publications.aap.

org/redbook/resources/25379. Children who have received nirsevimab should not receive palivizumab during the same RSV season.

†From time of maternal vaccination, at least 14 days are needed for the development and transplacental transfer of maternal antibodies to protect the infant. 
Clinical Considerations for Use of Maternal RSV Vaccine 

or Infant RSV Monoclonal Antibody

(Administration of both products is not needed for most infants)

Product Maternal RSV Vaccine RSV Monoclonal Antibody

Description RSVPreF vaccine

Trade name: AbrysvoTM

Generic name nirsevimab

Trade name: BeyfortusTM

Immunity Mother – Active immunity

Infant – Passive immunity

Passive immunity

Duration of Protection Approximately 3 to 6 months for infant Approximately 5 months or more

How Supplied A kit that includes a vial of lyophilized 

antigen component, a prefilled syringe 

containing sterile water diluent, and 

a vial adapter. The lyophilized antigen 

component is reconstituted with the sterile 

water diluent to form a single dose.

Single dose pre-filled syringe with a 

purple (for 50 mg dosage) or light blue 

(for 100 mg dosage) plunger rod. No 

reconstitution needed.

Recommended 

Dosage

0.5 mL

Currently recommended for administration 

as a single dose. It is not yet known whether 

additional doses might be needed in later 

pregnancies.

Age less than 8 months

• Less than 5 kg: 50 mg (0.5mL) 

• 5 kg and greater: 100 mg (1mL) 

Age 8 through 19 months‡

• 200 mg (administered as two IM 

injections)

Number of Doses One One§

How Administered IM injection IM injection

Coadministration Can be administered without regard to 

timing of other routine immunizations, 

including simultaneous administration

Can be administered without regard to 

timing of other routine immunizations, 

including simultaneous administration

Gestation or Age for 

Immunization

32 through 36 weeks • Less than age 8 months depending on 

mother’s RSV vaccination status

• Ages 8 through 19 months if at 

increased risk for severe RSV disease.‡

When to Administer 

(Seasonality)

Beginning of September through end of 

January in most of the continental United 

States.

In jurisdictions with RSV seasonality that 

differs from most of the continental United 

States, including Alaska, southern Florida, 

Guam, Hawaii, Puerto Rico, U.S.-affiliated 

Pacific Islands, and U.S. Virgin Islands, 

healthcare providers should follow state, 

local, or territorial guidance on timing of 

maternal RSV vaccination.

Beginning of October through end of 

March in most of the continental United 

States.

In jurisdictions with RSV seasonality 

that differs from most of the continental 

United States, including Alaska, southern 

Florida, Guam, Hawaii, Puerto Rico, U.S.-

affiliated Pacific Islands, and U.S. Virgin 

Islands, healthcare providers should 

follow state, local, or territorial guidance 

on timing of nirsevimab administration.

Contraindications

(Product Should Not 

Be Administered)

History of severe allergic reaction (e.g., 

anaphylaxis) to any component of the 

maternal RSV vaccine

History of severe allergic reaction (e.g., 

anaphylaxis) after a previous dose or to a 

component of nirsevimab
U.S. Department of 

Health and Human Services 

Centers for Disease 

Control and Prevention 

Precautions

(Administration Should 

Typically Be Deferred)

The presence of a moderate or severe acute 

illness, with or without a fever.

The presence of a moderate or severe 

acute illness, with or without a fever.

Safety • Local and systemic reactions

In clinical trials, the most common 

reactions after maternal RSV vaccine 

in pregnant people were pain at the 

injection site, headache, muscle pain, 

and nausea.

• Severe allergic reactions

As with any medicine or vaccine, there is 

a remote chance of RSV vaccine causing 

a severe allergic reaction

• Preterm birth

In clinical trials, among people who were 

vaccinated during weeks 24 through 

36 weeks of pregnancy, more preterm 

births were reported among maternal 

RSV vaccine recipients than among 

placebo recipients. This difference was 

not statistically different. Available data 

are insufficient to establish or exclude 

a causal relationship between preterm 

birth and maternal RSV vaccine. To 

reduce the potential risk of preterm 

birth when administering maternal 

RSV vaccine, FDA approved the vaccine 

for use during weeks 32 through 36 of 

pregnancy. The vaccine studies did not 

include people who already had a higher 

risk of preterm births.

• Hypertensive disorders of pregnancy

Although not common, in the clinical 

trials, hypertensive disorders of 

pregnancy (including pre-eclampsia) 

occurred in 1.8% of pregnant people who 

received the RSV vaccine compared to 

1.4% of pregnant people who received a 

placebo.

• Local and systemic reactions

In clinical trials, the most common 

adverse events after nirsevimab were 

rash and injection-site reactions, each 

occurring in <1% of infants and young 

children. 

• Severe allergic reactions

As with any medicine or vaccine, there 

is a remote chance of nirsevimab 

causing a severe allergic reaction.

• Serious adverse event

The incidence of serious adverse 

events was not increased in the 

nirsevimab arm compared with that 

in the placebo arm. No serious allergic 

reactions or immune complex disease 

were reported in the clinical trials.

‡Children 8–19 months who are at increased risk of severe RSV disease (American Indian and Alaska Native 

children; children who are severely immunocompromised; children with cystic fibrosis with severe disease; and 

children with chronic lung disease of prematurity who require medical support during the six months before the 

start of their second RSV season) should receive nirsevimab 200 mg dose administered as two IM injections (2 x 

100 mg light blue plunger rod) shortly before the start of their second RSV season.

§One dose for each RSV season except for children undergoing cardiac surgery with cardiopulmonary bypass 

where an additional dose is recommended as soon as the child is stable after surgery. See label (fda.gov).

Clinical Considerations for Use of Maternal RSV Vaccine 

or Infant RSV Monoclonal Antibody

(Administration of both products is not needed for most infants)

Product Maternal RSV Vaccine RSV Monoclonal Antibody