People under the age of 40 will be offered an alternative to the Oxford/AstraZeneca Covid-19 vaccine as a precaution amid blood clot fears.
The policy has previously applied to those under 30 but the age threshold has been raised after the Medicines and Healthcare products Regulatory Agency reported new figures on clots linked to the vaccine.
Last month Dr Amir Khan shared three blood clot symptoms recipients of the AstraZeneca vaccine jab should know about.
Dr Khan appeared on Good Morning Britain alongside hosts Adil Ray and Ranvir Singh after under-30s were told to get an alternative jab.
Dr Amir said: “It is common to get minimal side effects after having the vaccine such as headaches, a temperature, fevers, chills, but if your headache persists beyond four days after having the vaccine, then you should seek medical help.
“Other symptoms include blurred vision and nausea, and then as time develops, if you do not get treatment, that can progress then to seizures and such.
“But in particular headaches, blurred vision, nausea, particularly after four days, is when you should seek medical help.”
Despite the concerns at the time, Professor Adam Finn, from the University of Bristol and a member of the JCVI, said it was vital to keep vaccines going as society opens up, in order to help stave off rising infection rates.
Some European countries restricted the vaccine use in younger people following reports of low platelet counts and cerebral venous sinus thrombosis (CVST), a specific type of clot that prevents blood from draining from the brain.
After under 30s were told to seek alternative vaccines last month, Professor Adam Finn told BBC Breakfast discussed the possibility of using alternative vaccines for different age groups.
He said: “That’s certainly possible. We are seeing another vaccine coming in (Moderna), and further vaccines are approaching licensure, and I know that the UK has made contracts for quite a wide range of different vaccines.
“As time goes forward, we will have much more flexibility about who can be offered what.
“On the other hand, we do need to keep the programme going if the plan to open things up and allow things to get back to normal is to proceed without another wave of the pandemic coming through.
“So it’s quite a tricky balancing act here, getting the balance right, getting vaccines coming through… getting the risk-benefit right for people coming forward.”
Prof Finn told BBC Radio 4’s Today programme the reports of clots were being investigated “very seriously” and “very thoroughly”.
He said: “What stands out about them is that we see thrombosis, including thrombosis in the cerebral veins, all the time, but we don’t normally see them in association with a low platelet count – which is a small blood cell which is involved in blood clotting – and so that makes them stand out and makes us think that this is something a little bit different and out of the norm.”
Following research last month, the committee concluded that the benefits of the jab outweigh the risks, but as people under 30 are at less risk of coronavirus they should be offered an alternative jab.
That advice has now been extended to people under the age of 40.