The importance of temperature monitoring during the storage of vaccines

Vaccines play an important role in the quality of life by providing resistance against communicable diseases such as smallpox, measles and polio. Rapid urbanisation has increased the risk of contracting a communicable disease making vaccination that more important.

To maintain vaccine effectiveness, vaccines must be stored and handled properly. The effectiveness of vaccines are directly correlated to its proper handling and storage from time of manufacturing to delivery. Improper handling may result in:

  • Unsafe vaccines with potential health risks.
  • Money lost in unviable vaccines resulting in re-vaccination.
  • Reduced protection and decreased potency of the vaccine.

Vaccination storage and handling errors may ultimately have a devastating effect on the public’s perceptions. If vaccination is to become a common practise then the handling and storage of vaccines must be carefully managed by the manufacturer, healthcare distributor, provider and distributor.

The remainder of the article will look at the proper protocols for the storage and handling of vaccines.

Vaccine Handling and Storage (Handle with extreme care)

All healthcare facilities must have written procedures for routine storage and also for emergencies such as natural disasters, power failures etc. It is recommended that healthcare staff receive training for the following situations:

  • Accepting deliveries and ordering vaccines.
  • The proper procedures for storing vaccines.
  • Maintaining the proper vaccine stock levels.
  • Protocols for the disposal and handling of compromised vaccines.
  • Protocols for emergency vaccine storage.
  • Purchasing the correct storage units and determining the appropriate storage temperatures of vaccines.
  • How to properly use temperature monitoring equipment.

Clearly natural disasters and power outages is not the only way vaccines may become compromised. Leaving vaccines unrefrigerated for an extended period of time may have a detrimental effect on the vaccines potency and safety. In addition storing vaccines at the wrong temperature because of equipment failure or human error will also compromise stored vaccines.For this reason it is important that all staff members including security and custodial staff are well versed in the proper procedures for vaccine storage during natural disasters and power outages.

Vaccine Cold Chain

Vaccines must be kept at a specific temperature at all times (also referred to as the cold chain). Initially vaccines are kept in a cold storage unit at the manufacturing facility. During transportation vaccines are stored in a specially equipped cold storage truck where after it is stored in refrigeration units at its final destination.

Unfortunately heat is not the only enemy of vaccines, intense light and excessive cold may also reduce the vaccines effectiveness. Note that the potency of vaccines cannot be restored. It is important that storage of vaccines outside recommended temperature ranges should be immediately diagnosed and corrected by consulting the manufacturer.

Not all vaccines present with physical changes when compromised, therefore if there is a high likelihood that vaccines are compromised they should be discarded taking into account the proper disposal procedures.

Recommended storage temperatures (Refrigerator units – between 1.7°C and 8.3°C):

  • Influenza (LAIV, IIV, RIV),
  • HepA,
  • Meningococcal containing,
  • HepB,
  • Rotavirus (RV1 and RV5),
  • Human Papilloma Virus (HPV4 & HPV2),
  • HepA – HepB

Storage in freezer units (between -50°C and -15°C):

  • MMR,
  • HZC,
  • VAR,
  • MMRV

There are also vaccines that are extremely sensitive to freezing and in some cases; low temperatures may be more detrimental than high temperatures. For other vaccines consult with the manufacturer for proper storage temperatures.

Temperature Monitoring Equipment & Vaccine Storage

The proper vaccine storage equipment is essential to reliable vaccine supply. The health department recommend that refrigeration units should be stand alone units that either freezes or refrigerates and should under no circumstance be able to do both. Combination units typically have cold spots where vaccines will be frozen, also the temperature fluctuation within the unit is to variable for vaccine storage.

Providers should only consider units that have been custom-build or units manufactured by a pharmaceutical company.

Temperature Monitoring

The most important component in the cold chain is the vaccine thermometer. Fortunately providers have an extensive range of temperature monitoring equipment/devices to choose from.

Continuous Monitoring Devices

Continuous monitoring devices provide information on the duration that a storage unit has operated outside the manufacturers recommended vaccine storage temperature range and also when this deviation occurred. Comprehensive information is recorded on all temperatures at specific times. Continuous monitoring devices should have the following features:

  • Digital display that allows viewing of temperatures without opening the storage unit.
  • Warning mechanism to indicate that temperatures are outside the recommended temperature range.
  • Must be accurate to within +/- 0.5°C.
  • Should record short and long term temperature readings.

Digital Data Loggers

Digital data loggers are used for continuous temperature recording and monitoring and are usually battery operated. Data loggers are set to record at a user defined time interval making it possible to store and record thousands of discrete temperature readings. All data loggers are digital and most have specialized software allowing the user to download temperature readings with the option of determining the maximum and minimum readings and the time they occurred. Typical features are:

  • Warning mechanism for out-of-range temperatures.
  • A minimum of 4000 temperature storage readings.
  • Reading including maximum, minimum and current temperatures.
  • Programmable interface via a console or personal computer.
  • Must be VFC complaint.

Temperature Alarms

Temperature alarms notify healthcare staff that the storage unit is experiencing temperature problems. Overall,temperature alarms are only effective if responded to promptly.

Handling and storing vaccines requires careful monitoring by healthcare staff, appropriate emergency protocols and correct equipment. Having the correct vaccine thermometers and storage equipment will ensure the safety and efficacy of your facilities vaccines provided that staff are properly trained and respond to emergencies in a timely manner.