This site is intended for health professionals only

Chain reaction: ordering and storing vaccines

Judith Moreton
MSc SRN RHV
Programme Manager and Technical Adviser
Immunisation Division Department of Health

The aim of any immunisation programme is to protect the individual, their family and community from vaccine-preventable infectious diseases.  
Vaccines are biological substances that are sensitive to heat, cold and light and that naturally biodegrade over time, resulting in a loss of potency. This process is accelerated and irreversible if proper storage conditions are not adhered to and can result in failure to protect the individual, as well as wastage and other unnecessary costs for surgeries and the NHS.
Policies should be in place via primary care trusts (PCTs) (or NHS boards in Scotland) to ensure that all staff involved with immunisation are properly trained and adhere to local practice in accordance with national policy for the ordering, storage, stock control, distribution, transport and disposal of vaccines.
National policy, as contained in the leaflet entitled Immunisation against Infectious Diseases (1996 - The Green Book), a publicly available document on immunisation against infectious disease, is currently being updated, and new information regarding the cold chain, ordering and storing vaccine will become available from: www.dh.gov.uk/PolicyAndGuidance/HealthAndSocialCareTopics/GreenBook/fs/en

The cold chain
The cold chain is the standard procedure for handling vaccines.(1,2) It is the process by which vaccines must be kept between 2°C and 8°C during distribution, storage and administration.   
Vaccines must not be frozen as this may cause increased reactogenicity, and fracture of glass vials can lead to contamination and loss of potency, rendering the product ineffective.
Vaccines must not be used after the stated expiry dates or if they have not been stored or distributed correctly. Only the manufacturers of BCG and meningococcal C vaccines have given specific written guidance on usage if the cold chain has been broken.(3)

Ordering and storing
Overordering of vaccines on the national childhood programme, particularly when vaccines are in short supply, can leave children unprotected and vulnerable to preventable infections. Table 1 highlights the problems caused by overordering.

[[NIP23_table1_72]]

There must be at least two designated and trained people in the practice to cover all those who are responsible for the ordering and receipt of vaccines.
Responsibilities must include:

  • Maintaining an adequate supply.
  • Checking each delivery for leakage, damage and discrepancies.
  • Managing receipt of vaccine directly into refrigeration.
  • Maintaining the cold chain.
  • Minimising the risks of overordering.
  • Rotating stocks so that those with shorter expiry dates are used first.

A stock of 2-4 weeks' supply is sufficient for routine provision. An easy formula for determining the monthly requirement for childhood vaccines is:
 
No. of children born/year × No. of doses + 10% = No. of
                              12                                         doses/month  
Regular deliveries from the specialised pharmaceutical company that supplies these vaccines allow for smaller quantities to be ordered. For the annual influenza campaigns, manufacturers can stagger deliveries, thus avoiding overstocking of refrigerators.
Vaccines should be kept in their original packaging to protect them from temperature changes and exposure to light. They should be stored in the refrigerator with sufficient space for air to circulate - and never stored in the door, drawers or adjacent to the freezer plate.
Written records including vaccine type, brand, quantity, batch numbers, date and time received should be kept for audit.

Vaccine refrigerators
All vaccines and diluents must be stored in refrigerators specifically designed for the storage of pharmaceutical products and never in domestic refrigerators. On no account should food, drink or medical specimens also be stored in the same refrigerator. As vaccines are prescription-only medicines (POMs), they must be stored in either a locked refrigerator or a room that is locked when not occupied by a member of staff.

Monitoring
To maintain the cold chain the electricity supply must not be interrupted. A switchless socket or warnings taped over the plug should be used.
There must be continuous monitoring of the temperature, with digital maximum-minimum thermometers used according to the manufacturer's recommendations to identify when the temperature may have been out of range.
A written recording of the temperature for audit should be made at least once every working day, and digital thermometers reset and replaced according to manufacturers instructions.
Backup refrigeration must be available during defrosting or breakdown, and a written record of information on regular servicing, defrosting and cleaning kept for audit purposes.

Audit
All vaccines in the national childhood programme are inventoried in and cold-chain monitored to delivery points by the specialist pharmaceutical company that distributes them. By keeping accurate records, which are audited at least once a year, nurses and other primary healthcare members involved in immunisation programmes can ensure the safety and effectiveness of all vaccines up to the point of administration.
 
The author would like to thank Loraine Gershon, Pharmaceutical Adviser to the Immunisation Division at the Department of Health, for her help in compiling this article.

References

  1. World Health Organization. Immunization in practice:a practical guide for health staff.Geneva, Switzerland: WHO; 2004.
  2. Department of Health.Immunisation against infectious disease. London: HMSO; 1996.
  3. Department of Health.Some questions and answers for BCG vaccine SSI. Available from URL: http://www.dh.gov.uk/assetRoot/04/07/64/79/04076479.PDF