RSV spreads from person to person through:

• Direct Contact — Having close physical contact with an infected individual, such as kissing a child or person on the face.
• Contaminated Surfaces — Touching hard or soft objects (like doorknobs, toys, and counters) that have the virus on them, and then touching your own eyes, nose, or mouth before washing your hands.
• Airborne Droplets — Inhaling respiratory droplets released into the air when a sick person coughs or sneezes nearby.

People who have an RSV infection are usually contagious for 3 to 8 days, but sometimes infants and people with weakened immune systems can continue to spread the virus for as long as 4 weeks.

RSV immunization can help protect people from severe RSV illness. There are two types of RSV immunizations: RSV vaccines and long-acting RSV monoclonal antibodies.

For Older Adults:

Three RSV vaccines are available for adults ages 50 years and older:

• AREXVY (GSK) 
• ABRYSVO (Pfizer)
• mRESVIA (Moderna)

There is no preference for one RSV vaccine over another.

• RSV vaccine is given as one dose and is not an annual vaccine.
• People who have already received an RSV vaccine should not receive another dose at this time.
• RSV vaccine can be given at any time of year, but the best time is in late summer or early fall, before RSV season begins.
• RSV vaccine can be given at the same visit as other vaccines.

See Immunization Recommendations below to learn who should receive an RSV vaccine.

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For Pregnant People:

• ABRYSVO (Pfizer) is the only RSV vaccine recommended for use during pregnancy to protect infants from severe RSV illness.
• RSV vaccination during pregnancy helps protect the baby during their first RSV season.

See Immunization Recommendations below to learn which pregnant people should receive the RSV vaccine and when.

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For Infants & Toddlers:

• Long-acting RSV monoclonal antibodies help protect infants and young children from severe RSV illness. They are not vaccines, but they protect against RSV in a similar way by providing ready-made antibodies.
• For most infants, either maternal RSV vaccination during pregnancy or an RSV monoclonal antibody given to the infant is enough to protect against severe RSV illness. Most infants do not need both.

Infants Younger Than 8 Months:

Two long-acting RSV monoclonal antibodies are available:

• Nirsevimab (BEYFORTUS™)
• Clesrovimab (ENFLONSIA™)

There is no preference between nirsevimab and clesrovimab for infants younger than 8 months.

In California, RSV antibodies are typically given from October through March:

• Eligible infants born October through March should receive an RSV antibody within one week after birth, ideally during the birth hospitalization.
• Eligible infants born April through September should receive an RSV antibody as soon as possible on or after October 1^st.

See Immunization Recommendations below to learn which infants should receive an RSV antibody.

Children 8–19 Months at Higher Risk for Severe RSV:

Nirsevimab (BEYFORTUS™) is available for certain children ages 8–19 months who are at increased risk for severe RSV illness and are entering their second RSV season.

• In California, eligible children should receive nirsevimab as early as possible between October and March.
• Clesrovimab (ENFLONSIA™) is not recommended for children ages 8–19 months.

See Immunization Recommendations below for conditions that may put a child at higher risk for severe RSV illness. Talk with your health care provider if you are not sure whether your 8–19-month-old child should receive nirsevimab.

Note: The recommended period for RSV immunization may sometimes extend beyond March based on RSV activity in California. If your infant is due to receive an RSV monoclonal antibody near the end of the recommended period, talk with your health care provider about the recommendations for the current RSV season.

See Immunization Recommendations below to learn which children should receive nirsevimab.

RSV immunizations can be given at the same visit as flu, COVID-19, and other recommended vaccines, when appropriate for the person’s age and eligibility.

RSV immunizations lower the risk of severe RSV illness. How well they work may vary based on a person’s age, health, and how much time has passed since immunization.

• According to the American Academy of Family Physicians (AAFP), all three RSV vaccines—AREXVY, ABRYSVO, and mRESVIA—provide adequate protection against severe RSV illness in adults ages 60 years and older.
• RSV vaccination during pregnancy is at least 70% effective in preventing RSV-related hospitalizations in infants.
• Nirsevimab (BEYFORTUS™) is at least 80-90% effective in preventing RSV-related hospitalizations in infants. Studies also shown that clesrovimab (ENFLONSIA™) has similar effectiveness.

Side effects from RSV vaccine are usually mild and temporary. They may include:

• Redness, swelling, and pain at the site where the vaccine was given
• Fatigue
• Fever
• Headache
• Nausea
• Diarrhea
• Muscle or joint pain

The Los Angeles County Department of Public Health endorses California Department of Public Health's (CDPH) respiratory virus season immunization recommendations. This guidance was developed in collaboration with California partners in the West Coast Health Alliance and informed by national medical groups, including the American Academy of Family Physicians, American Academy of Pediatrics, and American College of Obstetricians and Gynecologists.

RSV immunization recommendations depend on a person's age, pregnancy, health conditions, and risk for severe RSV illness.

Who SHOULD get immunized
Older Adults

RSV vaccine is recommended for:

• All adults 75 years and older
• Adults 50–74 years old with the following medical and other conditions who are at increased risk of severe RSV illness.

People may be at higher risk if they:

• Have chronic heart or lung disease (e.g., heart failure, coronary artery disease, congenital heart disease, chronic obstructive pulmonary disease, emphysema, asthma, interstitial lung disease, cystic fibrosis). Excludes isolated hypertension.
• Have end-stage renal disease or dependence on hemodialysis or other renal replacement therapy
• Have neurologic or neuromuscular conditions causing impaired airway clearance or respiratory muscle weakness (e.g., post-stroke dysphagia, amyotrophic lateral sclerosis, muscular dystrophy). Excludes history of stroke without impaired airway clearance.
• Have chronic liver disease (e.g., cirrhosis)
• Have chronic hematologic conditions (e.g., sickle cell disease, thalassemia)
• Have a weakened immune system
• Have certain other medical conditions, such as diabetes or obesity (body mass index ≥ 40 kg/^m2)
• Live in a nursing home or long-term care facility

Pregnant People

One dose of ABRYSVO (Pfizer) is recommended for pregnant people who are at 32 – 36 weeks gestation between September 1^st and March 1st.

If ABRYSVO (Pfizer) was received during a previous pregnancy, another dose is not recommended during a later pregnancy. Instead, the infant should receive a long-acting RSV monoclonal antibody for protection against severe RSV illness.

Infants Younger Than 8 Months

One dose of a long-acting RSV monoclonal antibody (nirsevimab [BEYFORTUS™] or clesrovimab [ENFLONSIA™]) is recommended for infants younger than 8 months who are born during or entering their first RSV season if:

• Their birthing parent did not receive a maternal RSV vaccine during the current pregnancy
• The birthing parent's RSV vaccination status is unknown; or
• Less than 14 days passed between RSV vaccination during pregnancy and the infant's birth.

Most infants born 14 or more days after maternal RSV vaccination do not need an RSV monoclonal antibody.

Children 8–19 Months

One dose of nirsevimab (BEYFORTUS™) is recommended for certain children ages 8–19 months who are at higher risk for severe RSV illness and are entering their second RSV season.

This includes:

• Children with chronic lung disease of prematurity
• Children with a weakened immune system
• Children with severe cystic fibrosis
• American Indian or Alaska Native children
• children born preterm, at <32 weeks gestation, regardless of the need for medication or other support
• children with hemodynamically significant congenital heart disease
• children with anatomic pulmonary abnormalities or neuromuscular disorders
• children with Down syndrome or other chromosomal differences

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When RSV Immunization Is Not Recommended

RSV vaccines: People who have had a severe allergic reaction to an RSV vaccine or any of its ingredients should not receive that vaccine. Talk with your health care provider if you have a history of severe allergies.

RSV monoclonal antibodies: An infant or child should not receive an RSV monoclonal antibody if they have had a severe allergic reaction to that product or any of its ingredients.

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When RSV Immunization May Not Be Needed or Recommended

• Older Adults: An additional RSV vaccine dose is not recommended at this time if you have already received one.
• Pregnant People: An additional dose of ABRYSVO is not recommended during a later pregnancy if you received it during a previous pregnancy. The infant should receive an RSV monoclonal antibody instead.
• Infants Younger Than 8 Months: Most infants whose birthing parent received ABRYSVO at least 14 days before birth do not need an RSV monoclonal antibody.
• Health Care Personnel: Working in a health care setting alone is not a reason to receive an RSV vaccine. Health care personnel should receive an RSV vaccine if they meet the age- or risk-based recommendations described above.

If you have insurance:

• Talk to your doctor or check with your local pharmacy to see what vaccines they offer.
• Most health insurance plans cover the cost of recommended vaccines for children and adults.

If you are uninsured or underinsured:

• Programs are available to help cover the cost of vaccines.
• Children 18 years or younger may receive vaccines at no cost through the Vaccines for Children (VFC) Program if they are:
  • Eligible for or are enrolled in Medi-Cal
  • American Indian or Alaskan Native
  • Uninsured (do not have health insurance)
  • Underinsured (private health insurance does not cover the full cost of vaccines)
• Adults who are uninsured or underinsured may be able to get free or low-cost vaccines at clinics enrolled in the Vaccines for Adults (VFA) program. For more information on who is eligible, read VFA Eligibility Based on Insurance Status.

Locating Vaccine Clinics:

• A list of free and low-cost clinics in Los Angeles County.
• Interactive county map to locate free and low-cost vaccine clinics.
• Call 1-833-540-0473 (Public Health InfoLine) for a list of free or low-cost vaccine clinics. This includes Vaccines for Children (VFC) provider locations that serve Medi-Cal eligible children and uninsured or underinsured adults.

Los Angeles County Department of Public Health:

• RSV Viruses
• Paying for Vaccines
• Respiratory Vaccines Dashboard

Other:

• RSV - What You Need to Know (CDPH)
• Vaccine Recommendations (CDPH)
• 2026 Immunization Schedules (AAP)
• RSV Immunization Information Statement (Immunize.org)
• RSV Vaccine Information Statement (VIS) (Immunize.org)

Respiratory Syncytial Virus (RSV) causes a substantial burden of illness in the United States, particularly among infants, young children, older adults, and people with certain underlying medical conditions. RSV is the leading cause of infant hospitalization in the United States and can cause serious illness, hospitalization, and death in people at increased risk. The burden of RSV varies from season to season.

For current estimates of RSV-associated outpatient visits, hospitalizations, and death in the United States, see CDC RSV Burden Estimates. 

For current RSV activity and respiratory illness surveillance data in Los Angeles County, see LAC DPH RespWATCH.

In Infants and Young Children

RSV infection can cause a variety of respiratory illnesses in infants and young children. It most commonly causes a mild, cold-like illness but can also cause lower respiratory tract infections, including bronchiolitis and pneumonia.

Infants are at highest risk for severe RSV disease, particularly during the first months of life. Severe illness can occur in otherwise healthy infants as well as in children with underlying medical conditions.

Adults

In adults, RSV usually causes an upper respiratory tract infection. Symptoms may include rhinorrhea, pharyngitis, cough, headache, fatigue, and fever. Mild RSV illness typically resolves in 1–2 weeks.

RSV can also cause severe lower respiratory tract disease and lead to hospitalization, particularly among older adults and adults with underlying medical conditions.

• See Reportable Communicable Diseases for reporting requirements for RSV.
• Click here for more information on reporting a Vaccine Adverse Event.
• Report adverse events when nirsevimab is administered alone, to FDA MedWatch or via phone 800-FDA-1088. When nirsevimab is administered with other vaccines, adverse events should be reported to VAERS.