The Covid-19 vaccination rollout across the UK has seen more than 10 million people receive their first doses so far. This includes care home staff and residents, and the over-80s, all of which are priority groups.
Since the rollout began, there have been several changes around administering the vaccine. These include changing the period between the first and second doses from three weeks to three months to ensure more people get the first dose quickly.
There could now be another change based on the results of a recently launched UK trial. The trial aims to determine whether giving people different Covid vaccines for their two doses could be as effective as giving them the same one for both doses.
Providing greater flexibility
There have been lots of issues lately with vaccine stocks and supplies, among other things. While the vaccination rollout has continued without any significant problems, any supply issues could impact continued efforts to vaccinate the whole country as quickly as possible. The success of the vaccination programme is vital to easing lockdown restrictions and getting life back to normal.
Using different vaccines for the first and second doses would give the health service far more flexibility. It means that even if there is an issue with the supply of one of the approved vaccines, others can be used to continue the rollout while avoiding disruption.
According to some scientists, there is also a possibility that using two different vaccines for the two doses could improve protection levels. This is something that experts will be looking at during the trial. However, vaccines minister Nadhim Zahawi confirmed the same vaccine would continue to be used for both doses until at least the summer.
More than 800 people to take part in the trial
The National Immunisation Schedule Evaluation Consortium is running the new study. More than 800 participants aged 50 and over have signed up to take part in England.
As part of the study, some will receive the Pfizer vaccine for their first dose, followed by the AstraZeneca one for their second. Others will receive the vaccines the other way around. The time between the two doses will be either four or twelve weeks.
Prof Matthew Snape from the University of Oxford is the chief investigator for the study. In an interview, he said, "It will be really interesting to see if the different delivery methods actually could lead to an enhanced immune response [in humans], or at least a response that's as good as giving the straight schedule of the same doses."
Other vaccines are set to receive approval over the coming weeks and months. According to reports, these may be used as part of the research when available.
Scientists have said other vaccination programmes involve using different vaccines to improve effectiveness and protection levels, such as the Ebola programme. Based on this, some scientists are confident that using two different Covid vaccines could prove successful.