The syncitial respiratory virus (VRS) is a respiratory infection that mostly affects children and is especially serious in newborns and children under two years, as well as in older adults and people with chronic diseases. It is very contagious and it is estimated that it causes around 3.6 million hospital income and the death of some 100,000 children under five years annually. 97% of these deaths occur in low and medium income countries where access to healthcare is limited.
There are vaccines to prevent VRS infection. One of them is Nersevimab, a type of prolonged action antibody that has demonstrated effectiveness to prevent respiratory infections from the syncitial respiratory virus in clinical trials. However, these tests are carried out in controlled conditions that do not always reflect real life, so it was necessary to evaluate how this medicine worked in different countries, clinical situations, and in all types of babies, including those most exposed to the virus.
Now, a new study has compiled data from five countries during the first season in which Norsevimab began in a generalized way, focusing mainly on Babies under 1 yearalthough some of up to 2 years have also been included. In all cases, they were compared to those who received Nersevimab with those who did not receive it, during the same season of the virus.
The results have been published in The Lancet Child & Adolescent Health And they show that Nersevimab is very effective in reducing hospital admissions by VRS (83% less), income in ICU (81% less), and serious respiratory infections (75% less). However, the duration of hospitalization was not reduced in babies who had to be admitted despite having received the medication. It was also observed that Nersevimab was more effective in babies over 3 months than in the little ones, and that its effectiveness varied between countries. The United States had the best results, followed by Spain and France.
A key measure of prevention in child immunization programs
This work was done following international guidelines known as prism, which ensure that scientific reviews are rigorous. Several medical databases were reviewed to find published studies between January 2023 and February 2025 on how NineSevimab works in the real world, that is, outside clinical trials. The language or the type of study was not limited.
For “real -world effectiveness” we refer to how this medicine acts when applied in daily practice, in real children, with diverse conditions, and not only in controlled environments such as those of clinical trials, the authors have explained in their article. The search focused on newborn babies, lower than one year, or those that were in their first season of exposure to the syncitial respiratory virus (VRS).
The main aspects that were analyzed to evaluate the effectiveness of the drug were: how many children needed hospitalization by the syncitial respiratory virus, how many entered intensive care, how many developed respiratory infections on the low roads (such as bronchiolitis or pneumonia), and how long they remained hospitalized.
The studies were organized and leaked with specific tools, and two researchers each reviewed separately. If they did not agree, a third party was consulted. Only studies with original data were included that compared children who received Nersevimab against those who did not receive it.
This analysis confirms that Nersevimab is a very effective tool to prevent complications from the respiratory virus in babies
Studies made in different countries were also valued and the results were grouped by age, country and type of study. In addition, the quality of each with a specific tool that helps detect possible errors or biases was proven. The results were analyzed using statistical methods to combine data and detect significant differences.
Regarding the limitations of the study, researchers have indicated that, although the results are very positive, some aspects must be taken into account; For example, that the majority of the studies were observational, which can introduce difficult errors to control, or that it was not possible to analyze the effect according to the baby’s gestational age, or if they had previous diseases.
They also recognize that the differences between countries in health systems or access to medication can influence the results, which could not be evaluated whether NSSEVIMAB is specifically helped against bronchiolitis, although this is included in serious respiratory infections, and that the time elapsed since vaccination can also affect protection, but there were not enough data to analyze it.
This analysis confirms that Nersevimab is a very effective tool to prevent complications from the syncitial respiratory virus in babies. Although it does not shorten hospitalization days if the sick child does significantly reduce the risk of needing hospitalization or intensive care, according to researchers in their conclusions.
It is likely that factors such as the age of the baby, its weight, the moment of vaccination or the situation of the health system influence its effectiveness. Therefore, it is important to continue investigating to optimize its use according to each country or risk group. Even so, the data supports its inclusion as a key measure of prevention in child immunization programs, they conclude.
Source: www.webconsultas.com