Gaps in Vaccine Availability

Lessons learned from practical experience of how to ensure vaccine supply year-round are not yet available. To ensure use of the latest vaccine formulation available, countries can opt to alternate between NH and SH formulations throughout the year as each becomes available. However, this option would require significant logistical capacities to replace the vaccine formulation in use with the most recent formulation becoming available. Another option is an extension of shelf-life of influenza vaccine to ensure vaccine supply year-round. This would require agreement between the vaccine manufacturer and regulators of the producing and ordering country. As a third option, local vaccine manufacturers can adapt their production timing to meet local vaccination needs. For more detail on such approaches, see Considerations of strategies to provide influenza vaccine year round.