RSV (Respiratory Syncytial Virus): What You Need to Know About This Infection

The discovery of Respiratory Syncytial Virus (RSV) dates back to the 1950s. In 1955, a virus was isolated from a group of 14 chimpanzees suffering from respiratory illness at the Baltimore Zoological Gardens. The virus was initially known as chimpanzee coryza agent (CCA).

This virus was later named respiratory syncytial virus or RSV after neutralizing antibodies were found in schoolchildren.

RSV Vaccine development

Although RSV was isolated in the late fifties, the journey to developing an RSV vaccine has been fraught with challenges.

Around the same time that RSV was discovered, the Salk vaccine, based on an inactivated poliovirus, proved highly effective against the polio virus. So, in the 1960s, researchers tested an RSV vaccine based on a formalin-inactivated RSV virus.

However, these trials were disastrous and introduced severe lung inflammation and even resulted in the deaths of two infants. This type of reaction is known as a vaccine-associated enhanced respiratory disease (ERD).

This halted further vaccine development for a while, but eventually, testing and research continued. As a result, effective vaccines are being authorized for use.

The US FDA approved the first RSV vaccine on March 03, 2023. The vaccine known as Arexy is approved for the prevention of lower respiratory tract disease from RSV in individuals 60 and older.

On July 17, 2023, the US FDA approved Beyfortus (nirsevimab-alip) to help prevent lower respiratory tract disease from RSV in newborns and infants born during or entering their first RSV season. The US Centers for Disease Control and Prevention (CDC) also recommends the vaccine for children aged 8 – 19 months who are at a higher risk of getting severe RSV.

RSV is a global virus that spreads year-round. In temperate climates, cases peak in winter, and in the tropics, RSV cases spike during the rainy seasons.

The virus usually infects almost all children by the age of two, with mild symptoms.

However, people at risk for severe illness include:

• Infants or babies 6 months of age and younger (particularly premature infants)
• Children with congenital heart disease or chronic lung disease
• Anyone with compromised immune systems (e.g., from cancer or chemotherapy)
• Adults with heart disease, lung disease, or other medical conditions
• Older adults (65 and older)

RSV epidemiology worldwide

RSV is a leading cause of lower respiratory infections in children worldwide and related hospitalizations. The viral infection affects over 64 million people a year and causes 160,000 deaths.

EU, UK, and Norway

According to the European Centre for Disease Prevention and Control (ECDC), RSV is responsible for 213,000 hospitalizations for children under 5 and about 158,000 adults in Europe, the UK, and Norway.

South America

PAHO (Pan-American Health Organization) and WHO (World Health Organization) warned about rising RSV cases in the South American region.

• Brazil: PAHO report a significant increase in RSV cases in Brazil since April 2023 in children under two. 11 babies were reported dead from severe respiratory infections from May-June 2023.
• Argentina: In 2023, flu season started early, and in 2023, cases are 56% higher than in 2019 (peak cases in the same season).
• Chile: most severe RSV outbreak in years, straining its pediatric ICUs and killing 4 infants.

USA

• In the United States, the CDC reports that every year, RSV causes 2.1 million visits with health care providers (non-hospitalizations) among children under 5 and up to 80,000 hospitalizations for the same age group, with 100-300 deaths.
• In adults 65 and older, RSV leads to 60,000 to 160,000 hospitalizations and up to 10,000 deaths annually.

RSV is highly contagious and spreads quickly.

It is mainly spread through contact with respiratory droplets (coughing, sneezing) from an infected person, direct contact with the virus by kissing, or by touching surfaces contaminated by an infected person.

The virus can also be passed on from one person to another when an infected person’s hands come in contact with the mucous membrane of another person, such as their eyes or nose.

RSV can also spread when respiratory secretions of infected individuals dry up on bedding, linen, and towels and then shared with others.

As a member of the family Paramyxoviridae, RSV is a single-stranded RNA virus. It enters the human body through the mouth or nose.

Initially, it replicates by attaching to the cells lining the respiratory tract (epithelial cells). Once attached, the virus enters the cells and takes control of their machinery to accelerate replication. The viral cells proliferate and begin to infect neighboring cells.

The RSV virus then causes inflammation and damage to the respiratory tract. The cells lining the airways become swollen and produce excessive mucus, leading to symptoms such as a runny nose and congestion.

Sometimes, the virus creates syncytia, which are fused cells that make it easier for RSV to spread within the respiratory tract. Synctia are a characteristic sign of an RSV infection.

In some instances, this type of infection may lead to severe RSV disease, particularly in young children and individuals with underlying health conditions. The virus can cause bronchiolitis, an inflammation of the small airways in the lungs, which can result in coughing, wheezing, and difficulty breathing.

RSV incubation period (time for symptoms to appear from the time of exposure) is 4 to 6 days.

According to the US CDC, signs of RSV include:

• Runny nose
• Cough
• Sneezing
• Fever
• Wheezing
• Lowered appetite.

Very young infants may experience only decreased activity, irritability, and difficulty breathing.

In cases of severe disease, RSV can lead to:

• Bronchiolitis, a lower respiratory tract infection
• Pneumonia

People are usually contagious with RSV for 3 to 8 days.

RSV is usually diagnosed through a physical exam by a healthcare professional, who will observe common symptoms such as coughing, wheezing, and breathing difficulties or rapid breathing.

Standard rRT-PCRs and antigen detection tests are effective in diagnosing RSV infections in infants and children.

The US CDC notes that older children and adults may need highly sensitive rRT-PCR assays. Antigen tests are not recommended in older children and adults with RSV.

RSV treatment can vary depending on the age group

For infants

• In infants, treatment typically involves supportive care by ensuring they are well-hydrated and rested.
• In some cases, hospitalization may be necessary, especially if the infant is experiencing severe symptoms or difficulty breathing.
• Medications such as bronchodilators or antiviral drugs may also be prescribed in certain situations.

For children

• For healthy children, similar supportive care is provided, including plenty of fluids, rest, and over-the-counter pain relievers to help manage fever and discomfort.

For adults

• In adults, treatment usually focuses on managing symptoms and providing supportive care, such as rest, fluids, and over-the-counter medications to alleviate fever and pain.
• In severe cases, hospitalization may be required, and antiviral medications may be prescribed if deemed necessary by the healthcare provider.

The best way to avoid RSV and other respiratory illnesses is to practice proper hygiene and limit contact with people who are ill.

The US CDC recommends staying home when sick, using a tissue to sneeze or cough in, and frequent hand washing, especially after touching surfaces and items that could be contaminated with the virus.

The CDC also advises to avoid close contact with others and sharing of utensils.

Good hygiene also extends to regularly cleaning and sanitizing surfaces in your home, particularly high-traffic areas where people come into contact with each other.

What are the first signs of RSV?

According to the American Lung Association (ALA), the initial signs of RSV are similar to mild cold symptoms and include:

• Congestion
• Runny nose
• Cough
• Fever
• Sore throat.

Very young infants may have difficulty breathing and may be irritable.

How long does RSV last in children?

The Cleveland Clinic notes that RSV usually lasts between 3 to 7 days and that most people recover within 2 weeks.

Can you get reinfected with RSV?

Yes, RSV reinfections are common.

Does RSV go away on its own?

Yes, most RSV infections go away on their own, as per the US CDC. However, in some cases, it can cause severe respiratory symptoms.

Does Palivizumab prevent RSV?

Palivizumab is a monoclonal antibody medication recommended to prevent respiratory syncytial virus (RSV) infection in high-risk infants and children.

Palivizumab binds to the virus and prevents it from infecting cells. It is given as a monthly injection during the RSV season.

While Palivizumab is effective in reducing the risk of severe infection, it is not a guarantee and does not provide complete protection.

Other preventive measures, such as good hand hygiene and avoiding close contact with sick individuals, should also be practiced to further reduce the risk of RSV infections.

Can RSV be cured?

There is no cure for Respiratory Syncytial Virus (RSV), but in most cases, it causes mild to moderate cold-like symptoms and can be managed at home.

However, more serious symptoms can occur in some cases, including wheezing, severe coughing fits, and difficulty breathing.

Preventive measures for people at a high risk of getting RSV include the RSV vaccine, Palivizumab antibody medication, good hand hygiene, and avoiding close contact with infected individuals.

RSV is a highly contagious respiratory virus that primarily affects infants and young children. While most cases are mild to moderate, the virus can lead to severe respiratory infections and even death in at-risk individuals.

While there is no specific treatment or cure for RSV, preventive measures can be effective. They include getting the RSV vaccine (if eligible), Palivizumab antibody medication, and practicing good hand hygiene during peak RSV season. It is important to contact a health care provider for any medical advice on RSV or other infectious diseases.

For public health agencies, it is essential to keep an eye on local RSV outbreaks. This way, infected individuals can receive medical attention in time and lower the rates of hospitalization and death from RSV.

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