The cold vaccine chain is a temperature controlled supply chain that includes all equipment and procedures related to the vaccine. The cold chain starts with the cold storage unit in the production facility, the transport and supplier of the vaccine extends to the proper storage at the facility and ends with the administration of the vaccine to the patient. Manufacturers, distributors, public health personnel and healthcare providers share the responsibility to ensure that the cold vaccine chain is maintained from the moment the vaccines are produced to their administration.
Vaccine Storage and Processing Standard Operating Procedures (SOPs)
The CDC recommends that facilities develop and maintain clearly written, detailed and up-to-date storage and handling standard operating procedures (SOPs). SOPs are reviewed by all staff and updated annually by the vaccine coordinator. SOPs are planned for three main areas and contain information. These plans and information are as follows:
• General information: Includes contact information for vaccine manufacturers, equipment service providers, and key facility personnel, as well as job descriptions, regularly used forms and staff training requirements.
• Routine storage and use: Includes information on all aspects of vaccine inventory management, from ordering to monitoring storage conditions.
• Emergency vaccine storage, use and shipping: Steps to be taken in case of equipment failure, power outages, natural disasters or other emergencies that could endanger vaccine storage conditions.
Cold Vaccine Preparation
Vaccine preparation is the last step in the cold chain before administration. Careful handling and preparation of vaccines are just as important as proper storage. Things to do during preparation are as follows:
• Strict aseptic drug preparation practices must be followed.
Hand hygiene must be practiced before preparing vaccines.
• Vaccines should be prepared in a designated, clean drug preparation area away from the area where potentially contaminated items are placed.
Vaccines should be prepared one patient at a time and only when they are ready for administration
• Always check expiration dates and make sure the correct vaccine is chosen.
• Vaccines should only be administered by the person preparing it.
• The manufacturer’s instructions in the package inserts should always be followed.
Different Types of Vaccines
There is general information about different types of vaccine delivery, each type of preparation, storage conditions and applications are different. These types of vaccines are as follows:
Single dose vials (SDVs): A single dose vial (SDV) contains one dose and is used once for a patient. In order to get a dose, the vaccine from one SDV should never be combined with another.
Manufacturer-filled syringes: A syringe filled by the manufacturer (MFS) is prepared with a single dose of vaccine and sealed under sterile conditions by the manufacturer. An MFS does not contain a preservative to help prevent the growth of microorganisms. An MFS is designed for one patient and one injection, and once the sterile seal has been broken, the vaccine must be used or discarded at the end of the working day.
Multi-dose vials: A multi-dose vial (MDV) contains multiple doses of vaccine. MDVs can be pierced multiple times (using sterile technique) as they typically contain a preservative to help prevent the growth of microorganisms. Only the number of doses indicated on the manufacturer’s package insert should be withdrawn from the vial.
Reconstitution with diluents: Lyophilized (freeze-dried) vaccines can be in the form of a powder or pellet that must be mixed with a liquid (diluent) in a process known as reconstitution before administration. Liquid diluents vary in volume and composition and are specifically designed to meet the volume, pH (acid / alkali balance) and chemical requirements of the respective vaccines. Diluents are not interchangeable, unless specified by the manufacturer. A bottle of sterile water or normal saline should never be used to reconstitute the vaccines.
Pre-prepared vaccines: Vaccines should only be prepared during administration. General use syringes are designed for immediate administration, not storage. Contamination and growth of microorganisms can occur in syringes with pre-received vaccines without preservatives. Additionally, vaccine components may interact with polymers in a plastic syringe over time, potentially reducing the vaccine potential. Pre-prepared vaccines can also cause vaccine waste. Even for offsite clinics, vaccine manufacturers do not recommend the preparation of vaccines. Alternatively, the CDC recommends the use of MFSs for large vaccination clinics. If vaccines need to be withdrawn beforehand, the procedures to be followed are as follows:
• A separate application station should be set up for each vaccine type to avoid medication errors.
• Vaccines should only be prepared after arriving at the clinic or mass vaccination event.
• Each person administering the vaccine should not take more than one MDV or 10 doses at a time.
• Patient flow should be monitored to prevent unnecessary doses being withdrawn
• The pre-diluted vaccine should only be put into a syringe when ready for administration.
• If a previously taken vaccine is not used within 30 minutes of reconstitution, the manufacturer’s guidelines for storage conditions and time limits should be followed.
However, any remaining vaccines in pre-drawn syringes should be discarded at the end of the day and should never be returned to a vial to store previously drawn, reconstituted vaccine.
Arrangement and Storage of the Cold Vaccine Unit
For the most up-to-date storage and use recommendations for specific vaccines and diluents, always refer to the manufacturers’ product information and package inserts. There are important warnings for the arrangement and storage of the vaccine storage unit and these are as follows:
Storage of cold vaccine
Things to do to verify that vaccines are stored properly and to minimize the risk of application error are as follows:
• Vaccines should be stored in their original packaging with closed caps in separate containers until ready for administration to protect from light and provide additional thermal stability or protection. Never loose bottles or syringes filled by the manufacturer should be stored outside of their packaging. This increases the risk of application errors, exposes the vaccine to light, makes it difficult to track expiration dates and manage inventory. For specific purpose units, it is recommended that the vaccine be stored outside of the package. If this is the case, the manufacturer’s instructions for vaccine storage should be followed.
• Vaccines and diluents with the earliest expiration dates should be placed ahead of those with later expiration dates.
• Vaccines and diluents should be stored on different shelves with similar packaging or names or pediatric and adult formulations.
• Whenever possible, the diluent should be stored with the corresponding refrigerated vaccine and the diluent should never be stored in the freezer.
• Vaccines and diluents should be placed two to three inches from the unit walls, ceiling, floor and door.
• Vaccines and diluents should be arranged in rows and spaced to allow air circulation.
• If a domestic unit is used, it should be avoided to store vaccines and diluents that do not provide constant temperatures or adequate airflow in the unit, for example directly under the cooling holes, in deli, fruit or vegetable drawers or in the refrigerator door.
• Water bottles should be placed on the top rack, on the floor, and on the door shelves of a household unit, as placing water bottles in the unit can help maintain stable temperatures. However, water bottles are not recommended for use with certain pharmaceutical grade units.
• Avoid placing or storing anything other than vaccines, diluents and water bottles inside the storage units. If other medicines and biological products are to be stored in the same unit as vaccines, they should be clearly marked and stored in containers or boxes separate from vaccines. Potentially contaminated items (eg blood, urine, feces) should be appropriately stored and stored under vaccines to prevent contamination from drips or leaks.
• TMD should be placed in the middle of the unit with the surrounding vaccines. A DDL should be set to measure the temperature at least every 30 minutes.
Refrigerators should be kept between 2 ° C and 8 ° C (36 ° F and 46 ° F) and freezers should be kept between -50 ° C and -15 ° C (-58 ° F and + 5 ° F). Refrigerator and freezer thermostats should be set at the factory set or medium temperature, reducing the possibility of temperature deviations. Thermostats are marked in a variety of ways and generally indicate levels of coldness rather than temperatures. The only way to know the temperature at which vaccines are stored is to measure and monitor it with a TMD.
Monitoring Vaccine Temperatures
To ensure the safety of vaccines, the storage unit should check and record their minimum and maximum temperatures at the start of each working day. If using a TMD that does not show the minimum and maximum temperatures, the current temperature should be checked and recorded at least twice. Temperature monitoring record sheet with information should be placed on or near each storage unit door. The information on this tracking record page is as follows:
• If a device is not used to record the minimum / maximum temperature or the minimum / maximum temperatures, the current temperature
• Name and surname of the person who controlled and recorded the temperature
Actions if a temperature deviation occurs
Unit doors should be checked throughout the day and at the end of each day to make sure they are tightly closed. Weekly, the storage unit should review the temperature readings for changes in temperature trends that may require action, such as adjusting the unit temperature, repairing and replacing storage or temperature monitoring equipment. However, temperature data should be kept for at least three years.
Temperature Trips (Out of Range Temperatures)
Temperature readings outside the recommended ranges in vaccine manufacturers’ package inserts are considered a temperature change and require immediate action. In this case, the steps to be taken are as follows:
• The primary or backup vaccine coordinator should be notified immediately or the problem should be reported to the higher units.
• Exposed vaccines should be labeled not to be used and they should be placed in a separate container from other vaccines in the storage unit, and the separated vaccines should not be discarded.
• The vaccine coordinator or supervisor should begin documenting the details of the event.
• Ensure that the temperature monitoring device layout control or unit temperature is set properly and standard operating procedures (SOPs) should be applied for temperature excursions of the facility.
• For guidance, vaccination program and vaccine manufacturer manufacturers should be contacted according to SOPs.
• Complete documentation of the incident, including actions taken and results, should be made.
In addition, vaccines should never be allowed to remain in a non-working unit for a long time. If a unit is believed to have failed, emergency SOPs should be implemented.