NHS England confirmed details of the trial run of vaccination in care homes during a webinar for primary care staff on 13 December.
The sites will break up packages of the Pfizer/BioNTech vaccine and use cool boxes packed with cooling gel to move smaller amounts of vaccine to care homes.
Deliveries of the vaccine come in a box containing 975 doses in 195 vials of five doses each, which need to be diluted and drawn up before administration.
The DHSC confirmed last week that 'sites with the necessary MHRA licence can split the vaccine packs' - and GPs have been told that stocks of the vaccine can be 'moved sites up to twice in any 12-hour period, once thawed'.
The seven sites will test how long it takes per care home resident to obtain consent, how the 'pack down' process of splitting up boxes of vaccine should work and how transportation should be managed.
Vaccines will be transported from primary care network (PCN) designated sites to care homes undiluted, with dilution and drawing up to take place at the care home.
Guidance published last week from the NHS chief pharmaceutical officer warned that the vaccine 'must not be transported after diultion' because it is not clear 'how much movement the vaccine can withstand'.
Care home vaccination
GPs and other staff preparing doses of the vaccine have been warned that when diluting the vaccine, it must be 'gently inverted' 10 times - and under no circumstances shaken - because excessive movement could mean 'the lipid nanoparticles may again degrade, or release the mRNA which is destroyed'.
GP sites involved in the care home trial run have been told that un-reconstituted vials of the vaccine have 'a shelf life of two hours at room temperature', and that 'once reconstituted vial has a shelf life of up to six hours'.
GPonline reported last week that the first vaccinations in care homes in England could go ahead this week after senior GPs involved in the regional rollout of the vaccine programme said they expected some care home residents would be vaccinated by first-wave GP sites.
The Joint Committee on Vaccination and Immunisation (JCVI) placed residents of care homes for older people and care home staff at the top of its priority list for rollout of the COVID-19 vaccine.
Some care home staff have been offered vaccination at around 50 hospital hubs across England over the past week.
Rollout of vaccination to care home residents in Scotland began on 14 December.