Respiratory Syncytial Virus, or RSV, in Florida: What to Know

RSV viruses on a black chalk board next to a stethoscope
Respiratory syncytial virus, or RSV, is a common, highly contagious virus that infects the lungs and breathing passages. In healthy adults and older children, RSV typically causes mild, cold-like symptoms. (Photo credit: Roobcio – Adobe Stock)

Fast Facts

What is RSV?

RSV is a cold-like illness usually resolves on its own, but can be more severe and potentially life-threatening in certain groups, such as the very young and the elderly.

Respiratory syncytial virus, or RSV, is a common, highly contagious virus that infects the lungs and breathing passages. In healthy adults and older children, RSV typically causes mild, cold-like symptoms. Most RSV infections resolve on their own. Infants, very young children and older adults, however, are vulnerable to developing severe RSV. In these groups, RSV can cause severe respiratory illness and may lead to pneumonia and other infections, hospitalization or death.

RSV Basics

64 million Globally, RSV infects an estimated 64 million people each year.

160k deaths Globally, RSV causes more than 160,000 thousand deaths.

58k hospitalizations In the U.S., RSV infections lead annually to 58,000 hospitalizations in children younger than 5.

6k-10k deaths In the U.S., RSV infections lead annually too 6,000 to 10,000 deaths in adults over 65.

Respiratory syncytial virus is the common name of the pathogen Orthopneumovirus hominis, a virus in the family Pneumoviridae.

The virus was previously thought to spread through droplets extruded by an infected person, or via physical contact with an infected person or contaminated surfaces, such as counters and doorknobs. Newer evidence, however, indicates its primary mode of transmission may be through aerosols emitted when people exhale, speak, sing, cough, sneeze or blow their nose. These aerosols may contain virus particles, which can stay suspended in the air for long periods of time.

RSV can also remain alive on environmental surfaces for several hours and on hands for 30 minutes.

Globally, RSV infects an estimated 64 million people each year and causes more than 160,000 deaths. In the U.S., RSV infections lead annually to an estimated 58,000 hospitalizations of children younger than five years of age and about 6,000 to 10,000 deaths in adults over 65.

RSV Outbreaks in Florida

Photomicrograph of RSV in an unidentified tissue sample.
Using indirect immunofluorescence microscopy, this photomicrograph revealed the presence of the respiratory syncytial virus (RSV) in an unidentified tissue sample, RSV is the most common cause of bronchiolitis and pneumonia among infants and children under 1 year of age. (Photo Credit: CDC/ Dr. Craig Lyerla)

Individual cases of RSV are not reportable in Florida, but the state tracks RSV outbreaks, as well as emergency room visits, hospitalizations and deaths with a diagnosis of RSV.

Outbreaks are common in schools, daycare centers and facilities for the long-term care of the elderly.

RSV outbreaks tend to be seasonal. In temperate climates and most of the U.S., RSV typically circulates beginning in the fall and peaking in winter. In Florida and other places with more tropical, humid climates, outbreaks can occur sporadically throughout most of the year.

Florida’s RSV season starts earlier and lasts longer than anywhere else in the U.S. Each year, RSV infections usually begin in Florida and the Southeast before spreading to other parts of the continental U.S.

The Florida Department of Health (FDOH) has identified five distinct RSV seasons in the state by region:

  • Northwest Florida – October to April
  • North Florida – September to March
  • Central Florida – August to March
  • Southeast Florida – January to December
  • Southwest Florida – September to April

Symptoms of RSV

The symptoms of RSV commonly occur in stages and can vary with age. These can include:

  • Coughing
  • Fever
  • Runny nose
  • Decrease in appetite
  • Sneezing
  • Wheezing

Very young infants with an RSV infection may have more severe symptoms. Their symptoms can include:

  • Irritability
  • Decreased activity
  • Breathing difficulties
  • Nasal flaring
  • Rapid breathing
  • Shortness of breath
  • Wheezing
  • Bluish skin in more severe cases

People Most Vulnerable to Severe RSV Infections

Toddler boy using nebulizer to cure asthma or pneumonia disease . Sick baby boy rest on patients bed and has inhalation therapy by the mask of inhaler. Respiratory Syncytial Virus (RSV).
RSV infections in infants can lead to bronchiolitis, a lower respiratory tract infection that causes swelling in the bronchioles of the lungs, or pneumonia. (Photo credit: Zilvergolf – Adobe Stock)

People of any age can become infected with RSV, and repeat infections are possible. Those infected with RSV may be contagious one to two days before developing symptoms and are usually contagious for three to eight days after becoming ill.

Some age groups are particularly vulnerable to developing a severe infection.

Infants and very young children

Most people will first experience an RSV infection as an infant or toddler, with 97% becoming infected by two years of age. RSV infections in infants can lead to bronchiolitis, a lower respiratory tract infection that causes swelling in the bronchioles of the lungs, or pneumonia. Twenty to 30% of infants develop lower respiratory disease with their first infection.

RSV is the leading cause of infant hospitalization in the U.S., with two to three out of 100 infants infected with RSV requiring a hospital stay. RSV is the most common cause of acute respiratory infections in children younger than five years old.

Globally, RSV infections cause one in every 50 deaths of children younger than five. In the U.S., about 100 to 300 children under five die from the disease each year.Premature infants and those with serious lung or heart disease have the highest risk of developing a severe RSV infection.

Older adults

Awareness of RSV’s ability to cause severe respiratory disease in older adults is increasing. Each year in the U.S., an estimated 60,000 to 120,000 adults 65 or older are hospitalized due to an RSV infection. Adults particularly at risk for RSV-associated hospitalization include those with underlying health conditions, such as chronic heart or lung disease or weakened immune systems, and people who are frail, in nursing homes or long-term care facilities or of advanced age.

RSV Treatment

An RSV infection can be diagnosed by obtaining a nasal swab and testing for the presence of the virus with rapid in-office tests (rapid antigen tests) or more sophisticated tests in the laboratory (PCR tests). Mouth swabs can also be used, especially for infants.

Most people recover from an RSV infection on their own within a week or two. Those with RSV should rest and drink plenty of fluids. Antibiotics and steroids are not effective for RSV.

Adults can manage pain and/or fever with over-the-counter medications. Consult a healthcare provider before giving children medication. A humidifier and nasal saline with gentle suctioning can also help relieve symptoms in children with mild RSV.

Infants and children admitted to the hospital with a severe RSV infection may receive supplemental oxygen, intravenous fluids, humidified air, and/or nasal suctioning. A ventilator may also be needed to assist their breathing.

RSV Prevention

In 2023, the Federal Drug Administration (FDA) approved two new vaccines and a monoclonal antibody for the prevention of RSV infections in certain vulnerable people.

Medical syringe needle with vaccine in doctor's hand
In 2023, the Federal Drug Administration (FDA) approved two new vaccines and a monoclonal antibody for the prevention of RSV infections in certain vulnerable people. (Photo credit: – Adobe Stock)

For older adults and pregnant people

The FDA approved two vaccines, known as RSVPreF3 and RSVpreF (sold under the respective brand names Arexvy and Abrysvo). Either vaccine may be used to prevent severe RSV-related illness in adults 60 years of age and older. In clinical trials, both vaccines were moderately to highly effective at preventing symptomatic RSV lower respiratory tract infections in older adults.

The FDA also approved the use of Abrysvo in pregnant individuals to prevent severe illnesses caused by RSV in their infants from birth to six months of age. The vaccine can be administered between 32-36 weeks of pregnancy.

The Centers for Disease Control and Prevention (CDC) recommends RSV vaccines for adults 60 and older and people who are 32–36 weeks pregnant.

For infants and very young children

In 2023, the FDA approved a long-acting monoclonal antibody known as nirsevimab (sold under the brand name Beyfortus) for the prevention of severe RSV in premature infants, as well as healthy infants and children up to two years old. Nirsevimab contains laboratory-made antibodies that mimic the immune system’s natural defenses against RSV and is given as a single-dose injection.

Another monoclonal antibody known as palivizumab (sold under the brand name Synagis) is recommended by the American Academy of Pediatrics (AAP) only for children with certain underlying medical conditions. Synagis has been in use for many years and requires monthly doses during the RSV season.

The CDC recommends a monoclonal antibody for infants. The Arexvy and Abrysvo vaccines are not recommended for young children.

According to FDOH, Florida’s unique trends in RSV activity and state surveillance data are important factors to consider in the prescription of prophylaxis in children at high risk for severe RSV infections.

Additional Resources


RSV vaccine Q&A

The U.S. Food and Drug Administration approved a vaccine manufactured by GlaxoSmithKline to prevent respiratory syncytial virus, or RSV, in older adults. In clinical trials, the vaccine, called Arexvy, proved high vaccine efficacy.

Hospital Resource

Respiratory syncytial virus (RSV)

Respiratory syncytial virus (RSV) is a very common virus that leads to mild, cold-like symptoms in adults and older healthy children. It can be more serious in young babies, especially those in certain high-risk groups.