The Pfizer/BioNTech and Oxford University/AstraZeneca vaccines are being rolled out across the UK, and up to February 2 more than 10 million people have now received their first vaccine dose. Nearly half a million people have also now received their second vaccine dose.
How many Covid vaccines doses are needed?
The Pfizer/BioNTech, Oxford University/AstraZeneca and Moderna vaccines have been approved for use in the UK.
The Pfizer/BioNTech and Oxford/AstraZeneca vaccines are administered in two doses.
When people are invited to book their vaccinations, they are asked to book their first dose and second dose appointments.
READ MORE: Can you drink apple cider vinegar straight?
The Joint Committee on Vaccination and Immunisation (JCVI) recommends the second Pfizer/BioNTech dose is administered between three to 12 weeks after the first dose is given.
For the Oxford/AstraZeneca vaccine, the second dose may be given four to 12 weeks after the first dose.
Further vaccinations are still in development, such as the Valneva vaccine, which the UK has ordered 100 million doses of.
A single dose vaccine from Johnson & Johnson has been found to be 66 percent effective against COVID-19 in trials.
The vaccine offered complete protection against hospitalisation and death from Covid-19 in trials, and the UK has ordered 30 million doses.
Dr Mary Ramsay, head of immunisations at Public Health England (PHE), told Sky News that mixing vaccines is not recommended and should only happen on “rare occasions”.
Dr Ramsay said: “We do not recommend mixing the COVID-19 vaccines – if your first dose is the Pfizer vaccine you should not be given the AstraZeneca vaccine for your second dose and vice versa.”
Dr Ramsay added: “There may be extremely rare occasions where the same vaccine is not available, or where it is not known what vaccine the patient received.
“Every effort should be made to give them the same vaccine, but where this is not possible it is better to give a second dose of another vaccine than not at all.”
Why is the Government prioritising first doses?
The second doses of both the Oxford/AstraZeneca and Pfizer/BioNTech vaccines can be administered up to 12 weeks after the first dose.
This change was brought in to vaccinate as many people as possible with one vaccine dose, to increase the amount of people with some protection against COVID-19.
A statement from the UK’s chief medical officers at the end of December 2020 read: “Based on JCVI’s expert advice, it is our joint clinical advice that delivery plans should prioritise delivering first vaccine doses to as many people on the JCVI Phase 1 priority list in the shortest possible timeframe.
“This will allow the administration of second doses to be completed over the longer timeframes in line with conditions set out by the independent regulator, the MHRA and advice from the JCVI.
“This will maximise the impact of the vaccine programme in its primary aims of reducing mortality and hospitalisations and protecting the NHS and equivalent health services.”