What Parents, Expectant Mothers, and Older Adults Should Know

When people think about respiratory illnesses, influenza and COVID-19 often come to mind first. However, Respiratory Syncytial Virus (RSV) has quietly been one of the most common causes of serious illness in infants for decades and can also cause significant complications in older adults. [cdc.gov], [cdc.gov] 

A Brief History of RSV

RSV has an interesting origin story. The virus was first identified in 1956 in chimpanzees experiencing cold-like symptoms and was originally called the “Chimpanzee Coryza Agent.” A year later, researchers discovered the same virus in infants with respiratory illnesses, leading to its new name: Respiratory Syncytial Virus.  

The name comes from its tendency to cause infected cells to fuse together into larger cells called syncytia. [journals.asm.org] Interestingly, some of the symptoms of RSV come not only from the virus itself, but from the inflammation that occurs as the immune system eliminates these infected cells. As syncytia is destroyed, the airways become swollen and fill with mucus and cellular debris. In tiny infant airways, this can contribute to wheezing, bronchiolitis, and difficulty breathing. [historyofv…ccines.org], [vaccinesafety.edu] 

RSV is nothing new; nearly every child will get RSV at least once before their second birthday. Most recover with nothing more than cold-like symptoms, but some babies develop much more serious illness. [cdc.gov], [cdc.gov] 

RSV Symptoms

Symptoms can include runny nose, congestion, cough, sneezing, fever, wheezing, and decreased appetite. 

For many children and adults, RSV looks a lot like a common cold. However, some infections progress to bronchiolitis or pneumonia, particularly in infants and older adults. [cdc.gov], [vaccinesafety.edu] 

How Does RSV Spread? 

RSV spreads very easily through coughing, sneezing, close contact with infected individuals, and touching contaminated surfaces and then touching your face. 

People can spread the virus before they even realize they’re sick, which helps explain why RSV moves quickly through households, schools, daycares, and communities. [vaccinesafety.edu], [historyofv…ccines.org] 

When Is RSV Season?

In most parts of the United States, RSV season occurs between October and March, with activity often peaking during the winter months. The timing can vary somewhat from year to year and by geographic region. [cdc.gov], [primarycar…liance.com]

RSV and Babies: Why So Much Focus on Infants?

Although almost everyone gets RSV eventually, much attention is placed on babies because they experience the highest rates of severe disease and hospitalization. RSV is the leading cause of hospitalization among infants in the United States. [cdc.gov], [cdc.gov] 

Very young infants can be more vulnerable because their airways are much smaller than an older child’s. Even minor airway swelling and mucus can make breathing difficult. Additionally, their immune systems are still developing. 

The greatest risk occurs during infancy, particularly among premature infants and babies with certain heart or lung conditions. [cdc.gov], [vaccinesafety.edu] 

Protecting Your Baby from RSV

One of the biggest advancements in recent years has been the ability to help protect babies before they ever become sick. Previously, only premature infants and infants with serious health conditions had access to RSV protection. 

Today, families generally have two options, and most babies only need one of them. [cdc.gov], [cdc.gov] 

Option 1: Vaccination During Pregnancy

The RSV vaccine is recommended during weeks 32 through 36 of pregnancy during RSV vaccination season. 

When a pregnant woman receives the vaccine, her immune system produces antibodies against RSV. Those antibodies cross the placenta and help protect the baby after birth. It’s the same general concept used for vaccines such as Tdap during pregnancy. [cdc.gov], [weence.com] 

The RSV vaccine has been studied extensively and is considered safe for use during the recommended stage of pregnancy. The most common side effects are mild and may include soreness at the injection site, fatigue, headache, and muscle aches. 

As with any medical decision, mothers should discuss the risks and benefits with their obstetric provider. [cdc.gov], [cdc.gov] 

The vaccine does not provide immediate protection. It takes approximately two weeks for the mother’s body to develop antibodies and transfer them to the baby. Once transferred, those antibodies generally help protect the infant through the first six months of life. [cdc.gov], [weence.com]

Option 2: RSV Antibody Protection for Babies

If a mother did not receive the RSV vaccine during pregnancy, the baby can typically receive a long-acting antibody injection after birth. 

Technically, this is not a vaccine. Instead of teaching the immune system to make antibodies, it provides antibodies directly, offering immediate protection. [cdc.gov], [pedspandem…etwork.org] 

The protection generally lasts through an RSV season, about five months or longer. [cdc.gov], [pedspandem…etwork.org]

Which Is Better: Pregnancy Vaccination or Infant Immunization?

Families often ask if one option is superior. 

The reassuring answer is that both approaches are highly effective at reducing severe RSV disease in infants. Current recommendations generally call for one method or the other, not both. [cdc.gov], [cdc.gov] 

The best choice often depends on timing, maternal vaccination status, and individual medical circumstances.

Why Are RSV Immunizations Recommended Only for Babies Under 8 Months?

The first RSV season is when babies face their highest risk. By the time children are older than 8 months, they typically have larger, stronger airways, more mature immune systems, and have a greater likelihood of previous RSV exposure. 

Researchers found that the greatest benefit comes from protecting babies during those earliest months when severe disease is most common. Some children with specific high-risk medical conditions may still qualify for protection during a second RSV season. [cdc.gov], [pedspandem…etwork.org]

Can a Protected Baby Still Get RSV?

Neither maternal vaccination nor infant antibody protection guarantees that a child will never get RSV. Their primary purpose is to prevent severe illness, hospitalization, and complications. [cdc.gov], [cdc.gov] So, while babies may still become infected, the illness is much less likely to become serious.

How Long Does Protection Last?

Current RSV prevention strategies are designed to cover a baby’s highest-risk period. 

• Maternal vaccination provides protection for approximately 6 months after birth. 

• Infant antibody protection lasts approximately 5 months or longer. 

Neither provides lifelong protection. [cdc.gov], [pedspandem…etwork.org] 

Will My Child Need Another RSV Immunization Later? 

Most babies only require protection during their first RSV season. Certain children with chronic lung disease, severe immunocompromise, cystic fibrosis, or other high-risk conditions may qualify for protection during a second season. [pedspandem…etwork.org], [cdc.gov]

What Else Can Families Do to Prevent RSV?

Vaccination and antibody protection are important, but they’re only one part of prevention. 

Helpful prevention strategies include frequent handwashing, cleaning high-touch surfaces, avoiding close contact with sick individuals, limiting newborn exposure to large crowds during peak season, covering coughs and sneezes, avoiding tobacco smoke exposure, and staying home when sick These habits help reduce transmission of RSV and many other respiratory viruses. [vaccinesafety.edu], [historyofv…ccines.org]

Can RSV Be Treated?

There is no medication routinely used to cure RSV in otherwise healthy children. Treatment is generally supportive and may include; clearing nose with suctioning or nasal saline, frequent offering of fluids, rest, fever-reducing medications when appropriate, monitoring breathing, and using a humidifier. Severe cases may require oxygen therapy or hospitalization. [vaccinesafety.edu], [en.wikipedia.org] 

RSV and Older Adults

RSV is often discussed in connection with infants, but it can also cause serious illness in older adults, including pneumonia, hospitalization, and worsening heart or lung disease. Adults age 75 and older, and adults ages 50–74 who are at increased risk should ask their healthcare provider whether RSV vaccination is appropriate. [cdc.gov] Vaccinations for this age group are typically administered at pharmacies.

Vaccination may not prevent every RSV infection, but it can reduce the risk of severe illness and hospitalization. Older adults can also lower their risk by washing hands often, covering coughs and sneezes, avoiding close contact with sick people, cleaning frequently touched surfaces, and staying home when ill. [cdc.gov] 

Looking Ahead to RSV Season

Public health experts continue to recommend RSV prevention for eligible infants, pregnant women, and at-risk older adults before community transmission increases in the fall and winter months. Families should talk with their healthcare provider about the timing that makes the most sense for their situation. [cdc.gov], [aafp.org]