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Respiratory-syncytial-virus infections, reinfections and immunity. A prospective, longitudinal study in young
Insights
Acquired immunity to respiratory syncytial virus (RSV) infections in children shows reduced reinfection rates but not full prevention. Ameliorating illness severity, not preventing infection, may be a realistic goal for immunoprophylaxis.
Area of Science:
- Pediatrics
- Immunology
- Infectious Diseases
Background:
- Respiratory syncytial virus (RSV) is a common cause of respiratory illness in children.
- Understanding acquired immunity to RSV is crucial for developing effective prevention strategies.
Purpose of the Study:
- To investigate the development of acquired immunity to respiratory syncytial virus (RSV) infections in children over a 10-year period.
- To assess the impact of prior infections on subsequent RSV illness severity and infection rates.
Main Methods:
- Longitudinal study of respiratory illness in normal children from infancy over 10 years.
- Immunity assessed by infection rates and clinical illness severity upon reinfection during RSV outbreaks.
- Statistical analysis of attack rates for first, second, and third infections.
Main Results:
- During epidemics, the attack rate for a first RSV infection was 98%.
- The attack rate for second infections was modestly reduced to 75%, and for third infections to 65%.
- Immunity from a single infection did not prevent reinfection a year later, but the third infection showed a considerable reduction in illness severity.
Conclusions:
- Acquired immunity to RSV in children leads to reduced reinfection rates but does not fully prevent subsequent infections.
- While complete prevention of RSV infection may not be achievable, reducing illness severity is a potential outcome of immunoprophylaxis.
- These findings suggest that ameliorating RSV illness severity, rather than solely preventing infection, should be a primary goal for immunoprophylaxis development.
Abstract:
To better understand acquired immunity to respiratory-syncytial-virus infections, we analyzed data from a 10-year study of respiratory illness in normal children who were followed longitudinally from early infancy. Immunity was measured in terms of failure to become infected or reduction in severity of clinical illness upon reinfection. Outbreaks of infections occurred seven times over the 10-year-period. During epidemics the attack rate for first infection was 98 per cent. The rate for second infections (75 per cent) was modestly reduced (P less than 0.001); that for third infections was 65 per cent. Age and history of infection both influenced illness. Immunity induced by a single infection had no demonstrable effect on illness associated with reinfection one year later; however, a considerable reduction in severity occurred with the third infection. These observations suggest that amelioration of illness--rather than prevention of infection--may be a realistic goal for immunoprophylaxis.