Boris Johnson has set out the difficulties faced in getting the Pfizer/BioNTech vaccine into care homes.
It means that when the first doses are rolled out next week they will not find their way into care homes.
This is despite the Joint Committee on Vaccination and Immunisation (JCVI) deciding that care home residents were among those who should be given the jab first.
The committee examined data on who suffers the worst outcomes from coronavirus and who is at highest risk of death.
But Mr Johnson explained the logistical problem in delivering the vaccine to the most vulnerable.
He told a Downing Street press conference: “Of course we want to get it into care homes to protect the most vulnerable as fast as we possibly can.”
But “the difficulty is in distributing the cases to care homes” as each case contains 975 vaccines and there is a need to avoid wastage.
The regulator MHRA has not yet authorised “the people who would be transporting the vaccine to the care homes to be able to affect the division themselves”.
There was a risk the vaccine could “degenerate” if it was “improperly handled”.
Mr Johnson said: “Our objective must be to use the vaccine stocks that we have to protect those who are most likely not just to fall ill but to succumb to the disease.”
England’s deputy chief medical officer Jonathan Van-Tam said the Pfizer/BioNTech vaccine was a “complex product with a very fragile cold chain”.
“It’s not a yoghurt that can be taken out of the fridge and put back in multiple times,” he told a Downing Street press conference.
“It’s really tricky to handle.”
Sir Simon Stevens, chief executive of NHS England, said pharmacies could be able to start vaccinating in January.
He said: “That will be followed in the subsequent weeks with GP practices coming together in each area to operate local vaccination centres and that will grow to over 1,000 places right across England where GPs will be in touch with their at-risk patients inviting people to come forward for vaccination.”
He added: “If the MHRA, the independent regulator, as we expect they will, give approval for a safe way of splitting these packs of 975 doses then the good news is we will be able to start distributing those to care homes.
“And then as even more vaccine becomes available finally we will be able to switch on large vaccination centres across the country and indeed invite local community pharmacists probably at the beginning of January to begin to offer vaccination as well.”
