It's getting cold and winter has arrived. With the winter comes respiratory syncytial virus (RSV) which is a common respiratory virus that causes mild flu like illness in adults but can cause severe symptoms in infants. RSV is known to be one of the leading causes of hospitalization of children in the USA and circulation of the virus usually occurs from the month of December to February.1 Most of the hospitalizations occur of infants in the initial months of life. Usually, RSV is managed symptomatically and is known to cause bronchiolitis in infants.
Nirsevimab is a long acting monoclonal antibody approved by the FDA to prevent RSV lower respiratory tract illness in infants less than 8 months. In 2023 the health authorities approved its use in infants in their first RSV season and vaccination of to be mothers during late pregnancy with RSV vaccine to prevent RSV in young infants. CDC-led research which was conducted at seven academic pediatric medical centers in the USA found that Nirsevimab is highly effective in reducing hospitalizations caused by RSV in children less than 5 years old.2 In JAMA Pediatrics a prospective, population-based surveillance research article was published titled "Respiratory Syncytial Virus Disease Burden and Nirsevimab Effectiveness in Young Children From 2023-2024" which studied the effectiveness of the new therapies. In the study around 28,689 children were enrolled with acute respiratory illness out of which about one-fourth had tested positive for RSV. Nirsevimab showed 89% effectiveness against medically treated RSV associated acute respiratory illness and 93% effectiveness against RSV related hospitalizations although about 442 infants received the treatment.
A typical seasonal pattern has been seen with RSV which peaks in December through February but due to the COVID-19 pandemic the patterns were changed. In the 2023-2024 RSV season lot many cases of RSV were seen in children less than 5 years and the disease burden was the same as in the pre-pandemic era. The use of the maternal RSV vaccine was so low that the outcome could not be commented upon. The impact of RSV in infants is quite and to prevent hospitalization preventive measures should be considered.
Reference:
- Shi T, McAllister DA, O'Brien KL, et al. Global, regional, and national disease burden estimates of acute lower respiratory infections due to respiratory syncytial virus in young children in 2015: a systematic review and modelling study. Lancet 2017;390:946-958.
- Heidi L. Moline et al, Respiratory Syncytial Virus Disease Burden and Nirsevimab Effectiveness in Young Children From 2023-2024, JAMA Pediatrics (2024). DOI: 10.1001/jamapediatrics.2024.5572
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