Understanding RSV
Respiratory syncytial virus (RSV) affects the airways and lungs and can be easily spread.1,2 While most cases are mild, RSV is a leading cause of lung infections in babies.2
Why are babies at greater risk of RSV disease than older children or adults?
RSV can infect anyone, but some people are more at risk of serious illness than others.3 During their first year of life, babies’ lungs and immune systems are still developing,
which makes them vulnerable to RSV disease.4
What happens when babies are too young to tell their parents about RSV? Their toys speak up for them!
Watch as toys come to life to tell the story of Sofia,
a baby battling with an RSV infection.
How do babies’ immune systems make them vulnerable to RSV?
A baby’s immune system continues to mature after birth, so it’s difficult for them to produce a strong enough immune response to protect against RSV disease on their own.5–7
How do babies’ lungs develop?
Babies’ lungs continue to develop throughout
infancy and childhood.8
In the first year of life, the airways in their lungs are very
small and fragile,9 and babies’ airways can be smaller
than the tip of a pencil.8
As in some other infections, when babies have an RSV infection, these narrow airways are much more likely to become blocked with mucus, which can make it difficult
for them to breathe.10
So, along with their developing immune systems,
their tiny lungs make babies vulnerable to
developing a severe illness following an RSV infection.8
How does RSV affect the lungs?11
1. RSV enters via droplets into the eye, nose, or mouth.
Adapted from Jain H et al. 2023.
What is the timeline of a typical RSV infection12?
When babies catch RSV, the virus will multiply in their body for around 3–5 days (we call this the incubation period).12 Following this, symptoms will start to show; these usually get worse around Day 5, and then get better 7–10 days after infection.12
Most cases of RSV disease are usually mild and will resolve within this time.2 But for some babies, symptoms can progress from cold-like to severe within a few days of infection.13
Following an RSV infection, a cough may linger for around 4 weeks and around half of babies may have a wheeze after being ill with RSV.12
Adapted from Eiland L. 2009 and the Centers for Disease Control and Prevention (CDC).
When concerned about the health of your child, seek medical advice.
Please note: This is an illustration of the common pattern of illness due to RSV, but time periods and symptoms may vary between individuals.
Click here to learn more about the symptoms and severity of RSV.
Footnotes & references
RSV, respiratory syncytial virus.
1. Chatterjee A et al. lnfect Dis Ther 2021; 70: S5-S16.
2. Piedimonte G and Perez MK. Pediatr Rev 2014; 35(12}: 519-530.
3. Kater J et al. Cureus 2023; 15(3): e36342.
4. Pickles RJ and De Vincenzo JP. J Patho! 2015; 235(2): 266-276.
5. Simon AK et al. Proc Biol Sci 2015; 282(1821): 20143085.
6. Lambert L et al. Front lmmunol 2014; 5: 466.
7. Esposito Set al. Hum Vaccin lmmunother 2016; 12(7): 1700-7706.
8. Di Cicco M et al. Pediatr Pulmonol 2021; 56(1): 240251.
9. Hussain M et al. Biochim Biophys Acta Mel Basis Dis 2017; 1863(12): 3226-3242.
10. Meissner HC. N Engl J Med 2016; 374(1): 62-72.
11. Jain Het al. Respiratory Syncytia! Virus lnfection in Children. June 2023. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024. Available at: https://www.ncbi.nlm.nih.gov/books/NBK459215/. Accessed: September 2024.
12. Eiland L. J Pediatr Pharmacol Ther 2009; 14(2): 75-85.
13. Smyth RL and Breary SP. Encyclopedia of Respiratory Medicine. Bronchiolitis, Elsevier Ltd. 2006.
14. Centers for Disease Control and Prevention (CDC). How RSV Spreads. Available at: https://www.cdc.gov/rsv/causes/index.html. Accessed: September 2024.