Many vaccines come either in prefilled syringes or ready to use multi-dose vials.

Others are freeze dried and need to reconstituted or mixed with a specific diluent, such as sterile water.
Vaccines with Diluents
Those that use a diluent include:
- MMR II
- ProQuad
- Varivax (chickenpox)
- Zostavax (shingles)
- ActHib and TriHIBit (Hib)
- Hiberix
- Menveo and Menomune (Meningococcal)
- Pentacel
- Rotarix
- Imovax and RabAvert (rabies)
- YF-VAX (yellow fever)
In addition to sterile water, vaccine diluents can include sodium chloride, distilled water, and vaccine antigens.
Unfortunately, the use of diluents can lead to errors when administering vaccines, from using the wrong diluent, using a drug instead of a diluent, to giving a diluent instead of a vaccine.
That’s what happened when 15 children in Syria died after being vaccinated with MMR. The drug Atracurium was used instead of the diluent for the MMR vaccine.
It is also what happened to the children in Samoa.
And that’s why people who give vaccines are taught to “Check the vial label three times to be sure you have chosen the correct vaccine product (and diluent, when applicable). Check the expiration date of the vaccine (and diluent) before using to be sure they are not out of date.”
More on Vaccines with Diluents
- Use Of Vaccines With Diluents
- Safety of vaccine administration
- Immunization error related reactions
- Know the “7 Rights” of Vaccine Administration
- Statement regarding interim findings of WHO assessment of deaths of children in Idleb Governorate, Syria
- No, “vaccine reactions” didn’t kill several children in Mexico
- Administering just the diluent or one of two vaccine components leaves patients unprotected
- When Vaccine Injury Isn’t Vaccine Injury