Effectiveness of Nirsevimab Immunoprophylaxis Administered at Birth to Prevent Infant Hospitalisation for Respiratory Syncytial Virus Infection: A Population-Based Cohort Study

Respiratory syncytial virus (RSV) infection is a frequent cause of hospitalisation in the first few months of life; however, this risk rapidly decreases with age. Nirsevimab immunoprophylaxis was approved in the European Union for the prevention of RSV-associated lower respiratory tract disease in infants during their first RSV season. We evaluated the effectiveness of nirsevimab in preventing hospitalisations for confirmed RSV infection and the impact of a strategy of immunisation at birth. A population-based cohort study was performed in Navarre, Spain, where nirsevimab was offered at birth to all children born from October to December 2023. Cox regression was used to estimate the hazard ratio of hospitalisation for PCR-confirmed RSV infection between infants who received and did not receive nirsevimab. Of 1177 infants studied, 1083 (92.0%) received nirsevimab. The risk of hospitalisation for RSV was 8.5% (8/94) among non-immunised infants versus 0.7% (8/1083) in those that were immunised. The estimated effectiveness of nirsevimab was 88.7% (95% confidence interval, 69.6-95.8). Immunisation at birth of infants born between October and December 2023 prevented one hospitalisation for every 15.3 immunised infants. Immunisation of children born from September to January might prevent 77.5% of preventable hospitalisations for RSV in infants born in 2023-2024. These results support the recommendation of nirsevimab immunisation at birth to children born during the RSV epidemic or in the months immediately before to prevent severe RSV infections and alleviate the overload of paediatric hospital resources.

[Level of knowledge, attitudes and the use of preventive measures among household contacts of COVID-19 cases after the acute phase of the pandemic]

BACKGROUND

Assessment of the level of knowledge and attitudes regarding COVID-19 and preventive measures in household contacts of COVID-19 cases after the acute phase of the pandemic.

METHODS

Survey among household contacts of COVID-19 cases conducted in healthcare centers in Navarre (1) and Catalonia (8) between May 2022 and July 2023. The frequency of use of preventive measures and the knowledge and attitudes towards COVID-19 were assessed through 12 items.

RESULTS

215 contacts participated who correctly used the preventive measures (>85%), except for facemasks (35.8%) and interpersonal distance (47%); >85% showed adequate knowledge (5/6 items) and >80% had a positive attitude (3/6 items). Moreover, 54.7% considered that COVID-19 negatively affected their life and 54.1% that it is better to develop immunity by getting infected than by vaccination.

CONCLUSIONS

Household contacts show a correct level of knowledge and positive attitude towards the disease and its preventive measures.