Disposable syringes are meant for administration of vaccines, not for storage. CDC recommends that vaccines that have been drawn into syringes by the provider be discarded at the end of the clinic day if unused. Manufacturer-filled syringes that have not been activated (i.e., have not had the needle guard removed or a needle attached) may be kept and used until their expiration date. A manufacturer-filled syringe does not contain a preservative to help prevent the growth of microorganisms. Once the sterile seal has been broken, the vaccine should be used or discarded by the end of the workday.