Respiratory Syncytial Virus (RSV) Overview

Respiratory Syncytial Virus (RSV): The Disease

Respiratory Syncytial Virus (RSV) is a common contagious respiratory virus that produces cold symptoms such as coughing, sneezing, wheezing, decreased appetite, fever and malaise. Most people who become infected with RSV will recover fully within a week or two without treatment.¹

Young infants and children, older adults, and individuals with immune system disorders and chronic health conditions are at an increased risk of RSV infection and may also be at an elevated risk of developing complications from the illness.² Complications of RSV infection include inflammation of the small airways within the lungs (bronchiolitis) and lung infection (pneumonia) and may require hospitalization for supportive care.³Click to read more about RSV disease

Respiratory Syncytial Virus (RSV): Vaccine Approval Status

Two RSV vaccines are under consideration by the Food and Drug Administration (FDA) and the ACIP for adults age 60 or 65 years and older, one by GlaxoSmithKline (GSK) and the other by Pfizer.⁴ Neither vaccine demonstrates the ability to prevent transmission of RSV and vaccine efficacy beyond the clinical trial follow-up time of six to seven months is not known.⁵

The FDA’s Vaccines and Related Biological Products Advisory Committee (VRBPAC) will meet on May 1 to consider the biologics license application (BLA) for Pfizer’s RSV vaccine ABRYSVO for use in infants from birth through 6 months of age by active vaccination of pregnant women.

Previous to this FDA meeting, Pfizer reported vaccine efficacy in infants to be 57.1 percent at 90 days after birth, waning to 51.3 percent at 180 days and 41 percent at 360 days. Vaccine efficacy for severe RSV was reported at 81.8 percent at 90 days after birth, waning to 69.4 percent at 180 days. Vaccine efficacy related to hospitalizations were reported to be 67.7 percent at 90 days after birth, waning to 33.3 percent at 360 days.⁶

As vaccines are approved by the FDA and recommended by the U.S. Centers for Disease Control (CDC) for use, NVIC will publish information on licensed RSV vaccines. To learn more about the RSV vaccines under development, read our recent RSV article (link).

Respiratory Syncytial Virus (RSV) Quick Facts

Respiratory Syncytial Virus (RSV)

• Respiratory Syncytial Virus (RSV) is a common respiratory virus with symptoms similar to a mild cold, such as coughing, sneezing, wheezing, decreased appetite, fever, and malaise.⁷ The virus is contagious and is transmitted through coughing and sneezing, and by coming into direct contact with the virus.⁸

• Young infants, children, older adults, and individuals with immune disorders and underlying chronic health disease are more at risk of developing RSV infection and suffering from complications of the illness.⁹ By two years of age, most infants and children will have had RSV;¹⁰ however, it is possible to have more than one infection throughout a lifetime.¹¹Click to read more Quick Facts 

 

What is Respiratory Syncytial Virus (RSV)?

Respiratory Syncytial Virus (RSV) is a highly contagious virus with symptoms of illness that include decreased appetite, coughing, sneezing, runny nose, wheezing, and fever that generally occur within four to six days after infection. Newborns and young infants may present only with symptoms of breathing problems, irritability, and decreased appetite. Infants and young children, as well as older adults, are considered most susceptible to RSV infection.¹

RSV is an enveloped virus belonging to the genus Pneumovirus, family Paramyxoviridae. It contains 11 proteins that are encoded by the non-segmented RSV genome. As a result of being non-segmented, the virus is unable to shift antigenically to cause significant pandemics. While new genotypes of RSV can occur, the older types do not disappear, allowing for both old and new types to circulate simultaneously for long periods of time.²

There are two different subgroups of RSV, A and B, with subgroup A thought to be slightly more virulent than B. The two groups are defined by the reaction of the major surface proteins, with the G protein of the virus helping to attach to the cells of the airway and the F protein assisting by entering the cells of the infected individual.³ Both RSV A and B can circulate at the same time, however, one subgroup usually predominates.⁴

Most RSV infections resolve within one to two weeks without treatment, although complications such as pneumonia or bronchiolitis can occur, resulting in hospitalization. By two years of age, most infants and children will have had RSV,⁵ however, it is possible to have more than one infection throughout a lifetime.⁶ Most adults who become infected will have symptoms of respiratory illness that include cold-like symptoms such as cough, runny nose, sore throat, fever, and general discomfort.⁷

RSV generally begins to circulate in the fall and peaks during the winter months in the U.S. and countries with similar climates; however, seasonality can change in communities from year to year.⁸

IMPORTANT NOTE: NVIC encourages you to become fully informed about Respiratory Syncytial Virus (RSV) and the Respiratory Syncytial Virus (RSV) vaccine by reading all sections in the Table of Contents, which contain many links and resources such as the manufacturer product information inserts, and to speak with one or more trusted health care professionals before making a vaccination decision for yourself or your child. This information is for educational purposes only and is not intended as medical advice.

Is Respiratory Syncytial Virus (RSV) Contagious?

Respiratory Syncytial Virus (RSV) is contagious and is transmitted from person to person. It is spread by coughing, sneezing, or by direct contact with the virus. A person can become infected by coming into contact with the respiratory secretions of an infected individual, usually through coughing or sneezing, or by touching the virus directly (ie kissing). It is also possible to become infected by the virus by touching contaminated surfaces and then touching the face.¹

Most infected individuals are usually contagious for between three to eight days, although some people can transmit the virus to others for up to two days before symptoms begin. Immunocompromised individuals may be contagious for up to one month.²

IMPORTANT NOTE: NVIC encourages you to become fully informed about Respiratory Syncytial Virus (RSV) and the Respiratory Syncytial Virus (RSV) vaccine by reading all sections in the Table of Contents, which contain many links and resources such as the manufacturer product information inserts, and to speak with one or more trusted health care professionals before making a vaccination decision for yourself or your child. This information is for educational purposes only and is not intended as medical advice.

What is the History of Respiratory Syncytial Virus (RSV) infection in the U.S. and other countries?

Respiratory Syncytial Virus (RSV) was initially identified in 1955 by JA Morris in laboratory chimpanzees housed at Walter Reed Army Institute of Research in Maryland.¹ The chimpanzees, which were used in polio vaccine research, exhibited symptoms of respiratory illness.² Morris was able to confirm that the viral agent, which was initially named Chimpanzee Coryza Agent (CCA), was contagious when he exposed a second group of chimpanzees to the infection.³

In February 1956, a laboratory worker was purposely exposed to the infected chimpanzees and developed symptoms that included a low-grade fever, runny nose, cough, and headache. The lab worker initially tested negative for antibodies, but positive two weeks later. Additionally, blood samples taken from young adults living near Walter Reed Army Medical Center but most infants and children were negative. Antibodies, however, were detected in young adults, of which eight were dwelling in the same army barracks as the initial laboratory worker.⁴

Robert Chanock, a pediatrician and virologist, from Johns Hopkins University began research to isolate a novel pathogen believed to be causing severe respiratory illness in infants While researching, Chanock discovered two additional agents in babies with croup and pneumonia that were identical to CCA.⁵ Johns Hopkins is located within a 30-mile radius of Walter Reed Army Institute, where CCA was initially identified.

Due to the similarity of the novel pathogens to CCA and its characteristics, Chanock suggested the virus be renamed “Respiratory Syncytial” virus.⁶ In 1960, the virus was found in over 50 percent of the young babies diagnosed with pneumonia or bronchiolitis in the Washington D.C. area and in 12 percent of older infants and young children and labeled as a “respiratory pathogen of major significance during early life”.⁷ By the early 1960s, the virus was identified in Australia and attributed to an epidemic of lower respiratory illness in infants.^{8 9}

By the early 1980s, RSV was considered the most significant lower respiratory infection in infants and children under the age of two, with most presenting with bronchiolitis and pneumonia. Most outbreaks were reported in the late fall and spring in the U.S. and lasted between two and five months.¹⁰

Public health officials report that between four and five million children develop RSV infection each year, ¹¹ with approximately 2.1 million resulting in outpatient treatment, between 58,000 and 80,000 requiring hospitalization, and between 100 and 300 deaths. Additionally, the virus is estimated to be responsible for between 60,000 and 120,000 hospitalizations and between 6,000 and 10,000 deaths in adults 65 years of age and older.¹²

Prior to 2020, the seasonality of RSV was well established in the U.S., with the season onset ranging from mid-September to mid-November, with the peak from late December to mid-February, and the off-set concluding in mid-May. Since 2020, however, there has been a shift in RSV infection patterns, with the southern U.S. experiencing an increase in cases in the spring and peaking in July. Health officials attribute the change in RSV patterns to disruptions from the COVID-19 pandemic.

Globally, researchers report that in 2019, there were an estimated 33 million lower respiratory infections associated with RSV, 3.6 million RSV hospitalizations, and 26,300 in hospital deaths related to RSV. Additionally, researchers estimated that approximately 101,400 RSV-associated deaths also occurred in children under the age of five years.¹³

IMPORTANT NOTE: NVIC encourages you to become fully informed about Respiratory Syncytial Virus (RSV) and the Respiratory Syncytial Virus (RSV) vaccine by reading all sections in the Table of Contents, which contain many links and resources such as the manufacturer product information inserts, and to speak with one or more trusted health care professionals before making a vaccination decision for yourself or your child. This information is for educational purposes only and is not intended as medical advice.

Can Respiratory Syncytial Virus (RSV) cause injury or death?

For most people, RSV is similar to the common cold, with symptoms that include coughing, sneezing, wheezing, fever, runny nose, and decreased appetite. In children under the age of six months, RSV symptoms may only include difficulty breathing, decreased appetite, decreased activity, and increased irritability.¹ Most people recover from RSV illness within one to two weeks without treatment.²

RSV infection that spreads to the lower respiratory tract can cause complications such as pneumonia or bronchiolitis (inflammation of the small airways of the lung). Symptoms of severe infection may include wheezing, cough, fever, difficulty breathing, and cyanosis (bluish discoloration of the skin caused by lack of oxygen). In infants, severe illness symptoms may include irritability, lethargy, rapid or shallow breathing, poor feeding, cough, and trouble breathing.³ It is estimated that one to two cases out of 100 require hospitalization, with premature infants and immunocompromised children being at highest risk for severe disease.^{4 5 6}

RSV complications in adults may include pneumonia or lung infection, and illness may worsen chronic underlying medical conditions such as asthma, congestive heart failure, and chronic obstructive pulmonary disease (COPD).⁷ Among adults 65 years of age and older, it is estimated that RSV illness causes 60,000-160,000 hospitalizations and 6,000-10,000 deaths a year.⁸

IMPORTANT NOTE: NVIC encourages you to become fully informed about Respiratory Syncytial Virus (RSV) and the Respiratory Syncytial Virus (RSV) vaccine by reading all sections in the Table of Contents, which contain many links and resources such as the manufacturer product information inserts, and to speak with one or more trusted health care professionals before making a vaccination decision for yourself or your child. This information is for educational purposes only and is not intended as medical advice.

Who is Most at Risk for Respiratory Syncytial Virus (RSV)?

Young infants and children are considered most at risk for developing Respiratory Syncytial Virus (RSV) infection. RSV is considered the most common cause of acute childhood respiratory illness and the leading cause of hospitalization during infancy.¹ It is estimated that between four and five million children become infected with RSV in the U.S. each year, with an estimated 58,000 to 80,000 resulting in hospitalization.²

More recently, health officials have also determined that RSV can impact older adults, especially those who are frail or who have underlying health conditions.³ The CDC estimates that between 60,000 and 120,000 older adults develop RSV infection that require hospitalization, with 6,000 to 10,000 of those contributing to death.⁴

Individuals with underlying immune diseases, such as those with HIV infection, are also considered to be at a higher risk for developing RSV infection. ⁵

IMPORTANT NOTE: NVIC encourages you to become fully informed about Respiratory Syncytial Virus (RSV) and the Respiratory Syncytial Virus (RSV) vaccine by reading all sections in the Table of Contents, which contain many links and resources such as the manufacturer product information inserts, and to speak with one or more trusted health care professionals before making a vaccination decision for yourself or your child. This information is for educational purposes only and is not intended as medical advice.

Who is Most at Risk of Complications from Respiratory Syncytial Virus (RSV)?

In infants and young children, those most at risk for developing complications from Respiratory Syncytial Virus (RSV) infection include infants born prematurely, infants younger than six months of age, children with neuromuscular disorders that impact their ability to clear their mucous membranes or swallow properly, and children under the age of two years who have underlying immune disorders, chronic lung disease, or congenital heart problems.¹

Environmental factors can also cause infants to develop complications from RSV infection. These include a lack of breastfeeding, exposure to tobacco smoke, and poor socioeconomic status. Complications from RSV infection generally occur in countries with limited public health resources and access to supportive treatments and basic care.²

Complications of RSV infection in children include inflammation of the small airways within the lungs (bronchiolitis) and lung infection (pneumonia). The CDC estimates that between one and two children out of 100 will require hospitalization for RSV infection, but that most recover fully with supportive care that may include oxygen, mechanical ventilation, and intravenous (IV) fluids.³

Adults, especially older adults with underlying health conditions, or who are frail, are at an increased risk of developing complications from RSV infection. This includes adults with chronic lung or heart disease, and those with immune disorders. Complications from RSV infection in this population include pneumonia, and the worsening of chronic illnesses such as asthma, Chronic Obstructive Pulmonary Disease (COPD), and congestive heart failure. In the U.S., it is estimated that between 60,000 and 120,000 RSV infections among older adults require hospitalization, with between 6,000 and 10,000 contributing to death.⁴

IMPORTANT NOTE: NVIC encourages you to become fully informed about Respiratory Syncytial Virus (RSV) and the Respiratory Syncytial Virus (RSV) vaccine by reading all sections in the Table of Contents, which contain many links and resources such as the manufacturer product information inserts, and to speak with one or more trusted health care professionals before making a vaccination decision for yourself or your child. This information is for educational purposes only and is not intended as medical advice.

 

Can Respiratory Syncytial Virus (RSV) be Prevented and are there Treatment Options?

Respiratory Syncytial Virus (RSV) can be prevented through common hygiene practices that include:¹

• Frequent and thorough handwashing with soap and water
• Covering sneezes and coughs with a tissue
• Avoiding close contact with others when ill and staying away from individuals who are sick
• Frequent sanitizing of surfaces that are touched often

Infants who are considered to be at high risk for RSV can be administered palivizumab, a monoclonal antibody, to prevent severe complications of RSV infection. This drug is administered intramuscularly (IM), and is recommended by the American Academy of Pediatrics to be given monthly, for five consecutive months, during the fall and winter months, or at any time during the year when RSV infections are similar to the fall and winter months.² Palivizumab is not effective as a treatment for an infant experiencing an active RSV infection.³

There are no specific treatments for RSV infection. Most infants, children, and healthy older adults who become infected will recover within one to two weeks without any medical intervention. The symptoms of RSV infection can be managed with over the counter pain and fever medication, fluid and rest.⁴

In cases where breathing problems or dehydration occurs, or if complications such as bronchiolitis or pneumonia develop, hospitalization may be necessary. The CDC estimates that between one and two children out of 100 will require hospitalization for RSV infection, but that most recover fully with supportive care that may include oxygen, mechanical ventilation, and intravenous (IV) fluids.⁵ Children and adults who require hospitalization are typically discharged from the hospital within a few days.⁶

IMPORTANT NOTE: NVIC encourages you to become fully informed about Respiratory Syncytial Virus (RSV) and the Respiratory Syncytial Virus (RSV) vaccine by reading all sections in the Table of Contents, which contain many links and resources such as the manufacturer product information inserts, and to speak with one or more trusted health care professionals before making a vaccination decision for yourself or your child. This information is for educational purposes only and is not intended as medical advice.

Respiratory Syncytial Virus (RSV) and RSV Vaccine Quick Facts

Respiratory Syncytial Virus (RSV)

• Respiratory Syncytial Virus (RSV) is a common respiratory virus with symptoms similar to a mild cold, such as coughing, sneezing, wheezing, decreased appetite, fever, and malaise.¹ The virus is contagious and is transmitted through coughing and sneezing, and by coming into direct contact with the virus.²


• Young infants, children, older adults, and individuals with immune disorders and underlying chronic health diseases are more at risk of developing RSV infection and suffering from complications of the illness.³ By two years of age, most infants and children will have had RSV,⁴ however, it is possible to have more than one infection during an individual’s lifetime.⁵


• Most individuals who develop an RSV infection will recover fully within one to two weeks without treatment. There are no specific treatments for RSV infection but symptoms can be treated with over the counter pain and fever medication, rest, and adequate hydration.⁶ Individuals, especially young infants with small airways, may develop complications such as inflammation of the small airways in the lungs (bronchiolitis) or lung infection (pneumonia). Hospitalization may be required for individuals who have breathing problems, or who become dehydrated. Most people who require hospitalization will be discharged within a few days.⁷


• Infants born prematurely, babies younger than six months of age, and young children with congenital heart and lung disorders, neuromuscular disorders, and those who are immunocompromised are at high risk of developing RSV infection and suffering complications.⁸ It is estimated that between four and five million children become infected with RSV in the U.S. each year, with an estimated 58,000 to 80,000 resulting in hospitalization.⁹


• Adults with chronic health diseases, older adults, and those with immune disorders are also at risk of developing RSV illness and suffering complications from infection.¹⁰ The CDC estimates that between 60,000 and 120,000 older adults develop RSV infection that require hospitalization, with 6,000 to 10,000 of those contributing to death.¹¹

Centers for Disease Control (CDC)

• Respiratory Syncytial Virus (RSV)

Vaccine Reaction Symptoms & Ingredients

NVIC’s Ask 8, If You Vaccinate webpage contains vaccine reaction symptoms.

Search for Vaccine Reactions

NVIC hosts MedAlerts, a powerful VAERS database search engine. MedAlerts examines symptoms, reactions, vaccines, dates, places, and more.

Reporting a Vaccine Reaction

Since 1982, the NVIC has operated a Vaccine Reaction Registry, which has served as a watchdog on VAERS. Reporting vaccine reactions to VAERS is required by federal law under the National Childhood Vaccine Injury Act of 1986. If your doctor will not report a reaction, you have the right to report a suspected vaccine reaction to VAERS.

IMPORTANT NOTE: NVIC encourages you to become fully informed about Respiratory Syncytial Virus (RSV) and the Respiratory Syncytial Virus (RSV) vaccine by reading all sections in the Table of Contents, which contain many links and resources such as the manufacturer product information inserts, and to speak with one or more trusted health care professionals before making a vaccination decision for yourself or your child. This information is for educational purposes only and is not intended as medical advice.

---

References: