Respiratory Syncytial Virus (RSV) is a common respiratory virus that infects the nose, throat, and lungs. While RSV often causes mild, cold-like symptoms, it can lead to more serious conditions like bronchiolitis or pneumonia in certain individuals. Understanding who is most susceptible to severe illness from RSV is important for awareness.
Age-Related Vulnerabilities
Age is a major factor influencing the severity of RSV infection, with two distinct age groups being particularly vulnerable. Infants and young children face significant risks due to their developing respiratory systems and immune defenses. Premature babies are at a higher risk for severe RSV due to their underdeveloped lungs and immune systems. Infants younger than 6 months old are also highly susceptible, often requiring hospitalization for severe RSV infection. RSV is the most common cause of bronchiolitis and pneumonia in children under one year of age.
Older adults, particularly those aged 65 and above, represent another group with increased susceptibility to severe RSV. Their immune systems naturally become less robust with age, making them more vulnerable to serious complications. Each year, RSV leads to an estimated 60,000 to 160,000 hospitalizations and 6,000 to 10,000 deaths among adults 65 and older in the United States.
Underlying Health Challenges
Individuals with pre-existing medical conditions face a higher risk of developing severe RSV. Chronic lung diseases, such as asthma, cystic fibrosis, and chronic obstructive pulmonary disease (COPD), significantly increase this susceptibility. Adults with COPD may be hospitalized more often than those without, and RSV can worsen their lung function. RSV can also trigger exacerbations in individuals with asthma.
Congenital heart disease (CHD) also elevates the risk of severe RSV, especially in infants. Infants with hemodynamically significant CHD are at a higher risk for RSV hospitalization and can experience more severe disease courses. RSV infection can further strain the heart’s ability to pump blood and deliver oxygen, leading to significant pulmonary hypertension.
Weakened immune systems, whether due to conditions like HIV/AIDS, cancer treatments, organ transplantation, or certain medications, also increase vulnerability. These individuals have a reduced ability to fight off infections, making them more prone to severe RSV. Neuromuscular conditions that affect swallowing or breathing, such as muscular dystrophy, can also increase the risk of severe RSV outcomes. These conditions can impair a person’s ability to clear respiratory secretions, leading to more severe lung infections.
Environmental and Lifestyle Influences
Certain external factors and lifestyle choices can also contribute to an elevated risk of RSV infection or increase its severity. Exposure to secondhand smoke is a notable risk factor, particularly for infants. Secondhand smoke can damage airways and suppress immune responses, making individuals more susceptible to severe RSV symptoms and inflammation.
Crowded environments facilitate the rapid transmission of RSV. Places like daycare centers, schools, and nursing homes are common settings for outbreaks due to close contact among individuals. Seasonality also plays a role, with RSV infections being more common during specific times of the year, typically peaking in fall and winter months. This seasonal pattern increases the overall risk of exposure during these periods.
For infants, a lack of breastfeeding can indirectly increase RSV risk. Breast milk provides protective antibodies that help bolster an infant’s immune system. Infants who are not breastfed may miss out on these antibodies, potentially increasing their susceptibility to RSV and other infections.