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Wednesday 28 September 2016
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Insight: Ultimate guide to vaccine storage safety

Insight: Ultimate guide to vaccine storage safety

Correct storage and handling of vaccines is vitally important to ensure efficacyand reduce waste 

Over the years, the UK immunisation programme has continually evolved to meet increasing expectations for better protection and increased efficacy of vaccines. Public support and confidence in immunisation programmes remain at good levels with increasing demands for new vaccines to be introduced. NHS England, in commissioning services, recognise the importance of delivering a quality and effective immunisation programme that meets the expectations and demands of the general public. This is why NHS England has acknowledged the importance of vaccine management principles such as ordering, storing and handling vaccines in all immunisation service specifications to safeguard the quality, safety and credibility of the programme at a national and local level. 

Vaccine management

National guidelines and designated named persons

To ensure a quality and effective immunisation programme, it is important for all staff in the organisation to be familiar with national guidelines and recommendations for the ordering, storing and handling of vaccines1 in general practice. National guidelines and vaccine manufacturer’s summary of product characteristics (SPC) should be used to inform locally produced protocols that focus upon accurate records of vaccine stock, a continuous record of vaccine fridge temperatures and actions to be taken when temperatures fall outside the recommended +2°C to +8°C.2 This will ensure that all staff involved in delivering immunisation programmes understand the importance of maintaining optimum cold chain conditions so that vaccines remain potent and effective. 

The practice should also identify two designated individuals who will take responsibility for vaccine management in the practice. Ideally, this should include staffs from the nursing and management teams who have received training as per the national minimum standards; 3 who fully understand the importance of vaccine management and who have authority to take action when the recommended cold chain conditions have not been maintained. 

How often should the practice be ordering vaccines? 

Best practice recommendations encourage a good level of stock that is sufficient for the delivery of the routine programme for the forthcoming two to four weeks.4 Ordering small quantities of vaccine on a regular basis ensures that vaccines are used well within their expiry dates, prevents over-stocking of the vaccine fridge and in the event of a cold chain breach, limits the amount of vaccines that potentially may need to be discarded. Vaccine fridges should not be more than two thirds full and should allow good air circulation around all vaccines being stored. It is not good practice to bulk-order vaccines or overstock fridges. 

How should the practice be storing vaccines?

The delivery of vaccines in the UK is subject to a rigorous and robust cold chain procedure in which vaccines are stored as per the manufacturer’s recommendations. Once received in the practice, it is important for all staff to ensure that this level of commitment to maintain the cold chain is upheld. Designated practice staff should act swiftly to check the order for possible discrepancies or damage, and once accepted, ensure vaccines are immediately stored in their original packaging in a validated vaccine fridge. It is also important for designated staff to record the receipt of vaccines in the stock inventory record. 

A validated vaccine fridge must be: 

 - Suitable for the storage of vaccines between the recommended +2°C to +8°C.

 - Used solely for the storage of vaccines.

 - Locked or kept in a locked room.

 - Large enough to hold vaccine stock, while allowing enough space around the vaccines for air to circulate.

 - Wired into a switchless socket to avoid being turned off.

Domestic fridges are not identified as being a validated vaccine fridge and should not be used.

Vaccine fridges should be regularly cleaned and defrosted and receive, as a minimum, annual servicing to ensure optimum efficiency. It is important for all maintenance actions to be recorded and kept with the vaccine fridge1, ensuring a comprehensive service history that is easily accessible. 

What thermometers should the practice use and how often should temperatures be monitored? 

As a minimum requirement, two ‘max/min’ thermometers should be used with at least one being independent of the mains power supply to allow for continual monitoring in the event of electrical loss. In situations whereby the vaccine fridge already has an integrated thermometer, one max/min thermometer which is independent of the mains power supply should be used.

Temperature recordings should be undertaken at least once per day, ideally in the mornings so that any difficulties with the vaccine fridge during the night can be quickly identified. Best practice recommendations encourage at least annual calibration of all thermometers, with temperature log books being maintained and kept with the vaccine fridge. 

When monitoring the vaccine fridge temperature, the designated individual should remember the acronym of the ‘four R’s’. The acronym is an abbreviation of read, record, reset and react.1

Temperatures that fall outside of the manufacturer’s recommendations for storing vaccines should be immediately investigated to identify a cause and take remedial action, where necessary. In such situations, these vaccines become unlicensed products and are no longer covered by the manufacturer’s licensure. 

Stock management and auditing the vaccine fridge

The designated persons responsible for vaccine management within the practice should ensure that all vaccines are stored in their original packaging, vaccines can be tracked and accounted for and expiry dates are monitored so that those close to their expiry are used first. 

Local policies should also allow for regular audits of the vaccine fridge to be completed. Best practice recommendations include weekly audits of the contents of the vaccine fridge, monthly stock check and rotations and the sharing of audit results and temperature logs quarterly with the local screening and immunisation teams, if required. 

What is the cold chain and why is it so important? 

The cold chain is a system of transporting and storing vaccines within a recommended temperature range. Manufacturers recommend and state in their summary of product characteristics (SPC) that vaccines should be stored between +2°C to + 8°C1 to ensure the vaccine remains potent by the time it reaches the patient. 

Vaccines that are stored outside of the manufacturers recommendations can degrade over a period of time and can quickly lose their potency. Exposure to heat, cold, sunlight or fluorescent light can accelerate this process and once potency has been lost, it cannot be restored. This is why it is essential that the cold chain conditions are upheld from the place of manufacturer to the point of administration.5 

The designated persons responsible for vaccine management in the practice should aim to store vaccines at an actual temperature of +5°C to allow a safety margin of plus or minus 3°C. Maximum and minimum temperatures should not be outside of the +2°C to +8°C. 

A cold chain incident is whereby the temperature falls outside of the manufacturer’s recommendations for storage of vaccines. While there are varying degrees of significance, each breach in the cold chain should be immediately investigated. 

Issues for vaccines exposed to temperatures below 0°C

Exposing vaccines to freezing temperatures can result in irreversible damage that subsequently reduces vaccine efficacy. The extent to which damage occurs depends on vaccine type, the temperature the vaccine was exposed to and the time duration. For example, in order for some vaccines to elicit a strong and longer lasting immune response, some vaccines are bound to an adjuvant. Laboratory-based data suggests vaccines that are not bound to aluminium-based adjuvant freeze at a point well below zero and are able to withstand cooler temperatures before reaching freezing point - whereby aluminium-based adjuvants are irreversibly damaged by freezing temperatures and subsequently the level of efficacy cannot be guaranteed. 

Other examples include freeze-dried (lyophilised) viral vaccines and vaccine diluents. Freeze-dried vaccines are expected to remain stable at low temperatures but should not be frozen, whereby vaccine diluents should not be stored below 0°C due to potential bacterial contamination, such as hairline cracks that could increase the risk of localised reactions. 

In general, vaccines that are exposed to minimum temperatures of 0°C to +2°C are unlikely to be adversely affected by such an exposure, although specific vaccine stability guidance should be sought from each manufacturer. 

Issues for vaccines being exposed to temperatures above 8°C

When considering heat sensitivity of vaccines, the issues are often more complex due to limited data to validate the use of vaccine exposed to temperature above 8°C. In general, live attenuated vaccines are more sensitive to heat than inactivated vaccines. However every vaccine has different heat sensitivity and degradation rate, with the level of degradation accelerating as the temperature increases.5 Essentially, temperatures up to 37°C do not cause immediate loss of potency but can shorten the shelf life of vaccines and vaccines that are close to their expiry dates, degrade at a much faster rate. Therefore, when considering whether a vaccine has been adversely affected by the increase in temperatures, it is equally important to take into account the expiry dates of the vaccines exposed.

What actions should be taken when a cold chain breach has been identified? 

In the event that vaccines have not been stored as per the manufacturer’s recommendations, it is important for practice staff to act quickly and effectively to identify a possible cause. The cause may be straightforward such as the thermometer has not been reset after the previous reading or that the fridge door was left open for a short period of time such as taking a large delivery. In any event and whether the cause is known or not, the incident should be reported to the local Public Health England centre. 

Designated persons with responsibility for vaccine management in the practice should undertake the following actions when responding to an incident: 

 Embargo the fridge and vaccines

It is important that all vaccines exposed to temperatures outside of the manufacturers recommendations are embargoed inside the same fridge until a thorough investigation has been undertaken. If possible, the vaccine fridge environment should not change. The fridge should remain switched on at the electrical supply and vaccines should be labelled as not for use. It is important to maintain the same environment within the fridge as investigators may wish to validate the temperature using data loggers.

 Report the incident to the local Public Health England (PHE) centre

Once the fridge has been embargoed, report the incident immediately to the screening and immunisation or health protection team based at the local PHE centre. The PHE centre team will be able to provide specialist advice and ensure a thorough investigation and assessment is undertaken. Dependant on the severity, an incident team may be convened. 

 Collect as much information as possible

The PHE centre team will want the practice to collect as much information as possible so that a thorough risk assessment can be undertaken. Key information will include:

 - What monitoring has taken place, including max/min/actual temperatures, and how? The practice should ensure the temperature log is available for the team to review.

 - When was the fridge last serviced and when was the thermometer last calibrated? It is important to provide documentation where possible. 

 - When the cold chain was last guaranteed? 

 - What time periods are involved - hours, days or months? 

 - What was the temperature range during this period? 

 - Identify all vaccines stored in the fridge and provide records detailing how long they have been stored in the fridge, how often stock is being ordered and expiry dates of the vaccine involved. This information should be obtained from the stock inventory records and practice ordering records via ImmForm.

 - Request a refrigerator engineer to inspect the fridge.

The servicing of the fridge should be a priority.1 The engineers report may help the PHE centre team to establish a possible cause which will inform their risk assessment of the incident. 

Conclusion

Simple vaccine management principles are at the heart of delivering a high quality, safe and effective immunisation programme that patients and members of the public support and have confidence in. This credibility can easily be undermined by inappropriate ordering, storing and handling of vaccine at a local service level. Commissioners and providers need to be aware of their responsibility in the delivery of immunisation services, ensuring best practice recommendations and national guidance is incorporated locally to safeguard quality and effectiveness of the programme. 

 

References

Department of Health. 2013. Immunisation against infectious diseases: Storage, distribution and disposal of vaccines. TSO Publishing, Crown Copyright.[ Internet]

Health Protection Agency. Quality criteria for an effective immunisation programme. 2012.

Health Protection Agency. National minimum standards for immunisation training. 2005.

Public Health England. www.gov.uk/government/collections/immunisation " target="_blank">Protocol for ordering, storing and handling vaccines. 2014.

Health Protection Agency. Vaccine incident guidance: actions to take in response to vaccine errors. 2012.

 

Resources

Department of Health. Immunisation against infectious diseases: Storage, distribution and disposal of vaccines

Protocol for ordering, storing and handling vaccines

Vaccine incident guidance: actions to take in response to vaccine errors

Quality criteria for an effective immunisation programme