WHO guidance note: Vaccine diluents, revision 2015

A vaccine diluent is the liquid mixed with a lyophilized (freeze-dried) vaccine in order to reconstitute

the lyophilized vaccine and provide the final vaccine for administration. A vaccine diluent may be

sensitive to heat or freezing, and may require transportation and storage in the cold chain. This

guidance note outlines the proper handling and use of vaccine diluent, including, but not limited to,

critical steps for reconstituting vaccines safely.


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  • Vaccines & delivery devices


  • WHO


  • Policy and legislation

Topic references


Achieving immunization targets with the comprehensive effective vaccine management (EVM) frameworkUNICEF, World Health Organization (WHO)2016GuidanceEnglish
Cold room temperature mapping studiesWorld Health Organization (WHO)2018GuidanceEnglish
EVM assessment tools and user guidesWorld Health Organization (WHO)2019RepositoryEnglish
EVM Global Data AnalysisWorld Health Organization (WHO)2018GuidanceEnglish
EVM Standard Operating Procedures (SOPs)UNICEF, World Health Organization (WHO)GuidanceEnglish, French
How to Develop a Continuous Improvement Plan (cIP)UNICEF, World Health Organization (WHO)2018GuidanceArabic, English, French
Immunization supply chain and logistics - A neglected but essential system for national immunization programmesWorld Health Organization (WHO)2014GuidanceEnglish, French
Off-label use of vaccinesPieter Neels et al.2017Journal articleEnglish
Perception of health workers on the use of 30-day temperature recordersWorld Health Organization (WHO)2018GuidanceEnglish
Perception of health workers on the use of remote temperature monitoring systemsWorld Health Organization (WHO)2018GuidanceEnglish
Solar direct-drive vaccine refrigerators and freezers2017GuidanceEnglish
System design approach to improve the immunization supply chainWorld Health Organization (WHO)2018GuidanceEnglish
Temperature monitoring study: a fully documented process to detect weaknesses in the supply chainWorld Health Organization (WHO)2018GuidanceEnglish
Vaccine Management HandbookUNICEF, World Health Organization (WHO)2015GuidanceFrench
WHO guidance note: Vaccine diluents, revision 2015World Health Organization (WHO)2015GuidanceEnglish, French
WHO policy on the use of opened multi-dose vaccine vials (2014 Revision)World Health Organization (WHO)2014GuidanceFrench