Understanding RSV (Respiratory Syncytial Virus) in Infants

RSV is a common, contagious seasonal virus that will infect nearly all children by their second birthday¹. The RSV season typically runs from fall through spring in the northern hemisphere⁴. In temperate climates, RSV seasonality is aligned with the cold season, from late fall to early spring. In tropical and subtropical climates, RSV seasonality is less consistent with the peak usually aligned with rainy season and/or higher temperatures^{4, 5}.

In many cases, RSV causes mild cold-like symptoms, such as a runny nose, cough, or fever⁶. However, RSV is also the most common cause of lower respiratory tract infections in infants, including bronchiolitis and pneumonia ⁷. 

RSV is a leading cause of hospitalization in all infants, including healthy babies born at full term^{2, 3}. Most RSV-related hospitalizations occur in infants who were born healthy and without underlying medical conditions⁸. Older infants born before the RSV season are also at risk, accounting for around half of infant RSV hospitalizations^{9, 10}.

Beyond hospitalizations, RSV is responsible for a significant outpatient burden in children aged 2 and younger^{11, 12}. Around 1 in 5 children will require outpatient medical care because of RSV by the age of two¹³. Although deaths from RSV are uncommon in high-income countries, severe disease can still occur, even in otherwise healthy infants^{2, 7}.
Because RSV can affect any baby, regardless of their month of birth or overall health, understanding the virus, recognizing symptoms early, and learning about prevention options and measures are important steps in helping protect infants.

RSV symptoms often begin like those of a common cold, including a runny or blocked nose, cough, and sometimes a fever⁶. In most cases, these symptoms are mild and resolve on their own.

However, RSV can sometimes spread to the lower respiratory tract and cause more serious illnesses, such as bronchiolitis or pneumonia⁶. As the infection progresses, breathing difficulties may develop.

RSV is a highly contagious virus that spreads through respiratory droplets when an infected person coughs, sneezes, or talks. It can also spread through direct contact or by touching contaminated surfaces and then touching the nose, mouth, or eyes. RSV can survive on surfaces for several hours, making it easy to transmit in households and childcare settings^{6, 14, 15}. RSV is up to 4 times more contagious than influenza^{16, 17}.

Most people infected with RSV experience only mild, cold-like symptoms and may not realize they're carrying the virus, yet they can still spread it to others. RSV is most commonly spread to babies by:

• Older siblings who have been infected at school or daycare¹⁴
• Other children in daycare centers or play areas¹⁴
• Adults who may be momentary carriers without displaying symptoms¹⁸

Each person infected with RSV can spread the virus to an average of 4.5 people¹⁶, allowing it to circulate widely in the community.

There is generally no specific treatment for RSV itself. Instead, management focuses on relieving symptoms to help infants stay comfortable while their immune system fights the infection. In most cases, RSV infections can be managed at home with symptomatic care, though some infants may require medical attention or hospitalization depending on the severity of their symptoms. In the case of concern about a child's health, it's important to seek medical advice in a timely manner.

RSV is a highly contagious virus¹. While there is no specific treatment for RSV, there are preventative options available to help protect infants against RSV disease. A healthcare professional (such as a doctor, nurse or pharmacist) can provide more information about this.

Additionally, here are some preventive measures and barrier measures to help reduce the chance of an RSV infection³³