Using COVID-19 vaccines during hot weather

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Higher temperatures increase risks to safe vaccine use and storage. To minimise effects: control ambient temperature, assess risks, and mitigate against them.

Higher temperatures increase risk

Vaccines must be stored and used within temperatures specified by the manufacturer and MHRA-authorised conditions of use, to ensure their safety, quality and efficacy.

During the summer, there is an increased risk of temperatures in ambient areas rising above the maximum permissible storage temperature [25°C for Moderna (Spikevax),  and 30o C for Comirnaty]. This is particularly likely in venues that are susceptible to significant fluctuations in temperature such as vehicles, marquees, tents and some local community facilities.

Undertake an assessment

An assessment must be made of all areas in which vaccines may be stored, prepared and administered. The assessment should identify the necessary preventive measures that will need to be taken if ambient temperatures are thought likely to exceed 25°/30oC as applicable.

Increase monitoring frequency

Monitoring of temperatures in ambient preparation and administration areas is required.

Frequent measurements should be taken with a calibrated digital thermometer. The higher the temperature the more frequent the monitoring needs to be: for example, if the temperature is greater than 20°C in the work area the monitoring should be hourly. Action must be taken to prevent temperatures exceeding the permitted maximum, and if temperatures reach it, additional steps will need to be taken to protect the vaccines.

Control ambient temperature

Additional mechanical controls (e.g. portable air conditioning) may be used if available locally, either on a temporary or permanent basis, to maintain temperatures within the required range.

Reviewing and managing risk

You should continually review your risk assessment and manage the risks appropriately.

Continually review your risk assessment

It is important to review your risk assessment frequently as conditions change. You should undertake your assessment at the start of, periodically during, and after each vaccination session. If necessary, contact your site Lead Pharmacist for advice.

Manage risk

The following actions should be considered to reduce risks to the vaccine.

Optimise workflow and work area

Manage workflows from storage and preparation to administration to minimise the time the vaccine is outside cold storage and exposed to elevated temperatures. Consider removing only one vial at a time from the fridge.

Be aware that methods to improve comfort for staff by increasing air movement (e.g. use of fans and opening windows) do not normally lower air temperature, unless they move air from a cooler area to a warmer area.

Consider restricting the number of people working or waiting in the vaccine preparation area, and removing non-essential electrical equipment, as this may reduce the temperature slightly.

Store punctured vials appropriately

Minimise the period of exposure of punctured vials to elevated ambient temperatures.

You should:

  • Return them to the fridge when not being used. Follow our advice on using fridges appropriately
  • If it is not possible to avoid storing the punctured vial in the same fridge as un-punctured vials, mark the punctured vial clearly and segregate it within a clearly labelled box or bag.
  • Use a cool box if a refrigerator is unavailable. The cool box must be continuously monitored to ensure the internal temperature remains within 2-8°C. Follow our advice on using cool boxes appropriately.
  • Minimise the time the fridge door or cool box is open. Repeatedly opening the refrigerator or cool box will allow warm air to enter.  Make sure fridge doors or cool boxes are securely closed as soon as possible after opening.

Use in conjunction with other material

This page should be read in conjunction with other material covering cold chain management for COVID-19 vaccines.

COVID-19 Vaccines

Information and guidance from across SPS on pharmaceutical aspects of COVID-19 vaccines’ use

Update history

  1. Page reviewed and up to date for Autumn 2023 campaign
  1. Links updated
  1. Reviewed: no changes
  1. Reviewed and unchanged
  1. Temp references amended to reflect max 30C allowed for Comirnaty and brand names for all vaccines
  1. Published