Why was the live attenuated influenza vaccine (LAIV) removed from the ACIP's influenza vaccine recommendations?

The live attenuated influenza vaccine (LAIV) was removed from the Advisory Committee on Immunization Practices (ACIP) recommendations primarily due to the observed low effectiveness during specific influenza seasons, particularly the 2013-2014 and 2015-2016 seasons. Data collected during these times indicated that LAIV did not provide adequate protection against influenza virus infections, particularly in children.

This assessment was grounded in real-world effectiveness studies that demonstrated a much lower performance of LAIV compared to inactivated influenza vaccine (IIV) in preventing influenza. Consequently, this led to the decision to not include LAIV in the recommended vaccines for certain populations, as maintaining high vaccine efficacy is crucial for effective public health vaccination programs.

Other potential concerns such as vaccine safety or supply issues were not the primary reasons for its removal from recommendations, although those factors may contribute to overall vaccine decisions in a broader context. The focus on effectiveness was pivotal in shaping the ACIP's guidance regarding the influenza vaccination strategy.