New RSV Immunisation and Vaccination Programmes

Abstract Issue/problem Respiratory Syncytial Virus (RSV) is the most common cause of lower respiratory tract infection in infants, resulting in 101,401 infant deaths globally each year. Recent breakthroughs in RSV immunisation and vaccination technology have led to significant strides in protecting vulnerable infants from severe RSV infection. This abstract details findings from the initial two years since select countries began new RSV protection programmes with nirsevimab (newborn immunisation) and/or Abrysvo (maternal vaccination). Description of the problem We reviewed health service news bulletins, vaccination advisory body meeting proceedings, and early immunisation impact reports to assess each country's approach to deciding which infants met the “high risk” and “catch up” criteria for immunisation. We used health surveillance data from governmental sources to investigate the impact of RSV immunisation and vaccination on infant RSV hospitalisation rates across a number of countries, including the United Kingdom, Ireland, and the United States of America. Results Amongst the countries which have opted for immunisation, both the high-risk and catch up cohorts vary in terms of infant eligibility criteria. RSV immunisation programmes have reduced RSV hospitalisation rates amongst large cohorts of infants across many different countries, with no adverse outcomes recorded. Lessons The success of these new programmes supports the expansion of the catch up and high risk infant immunisation cohorts. A nuanced strategy, based on each country's regional and national morbidity data is likely to be of best use when deciding upon infant high-risk status. Increasing the age of the catch up cohort to all those who are ten months or less at the start of the RSV season could ensure that winter surges of RSV are comprehensively suppressed. A comprehensive approach to immunising these older infants could simplify rollout of nationwide immunisation programmes. Key messages • Vaccination and immunisation programmes against RSV have recently begun in some countries. These have succeeded in reducing infant hospitalisation rates; no major adverse outcomes have been reported. • International policies vary in deciding infant eligibility for nirsevimab; standardisation of the “catch up” cohort could help suppress winter RSV surges across neighbouring countries.