Can we boost immunity with the vaccines we have now?
What to make of the news this morning that Oxford University is to ask for volunteers to take part in a trial to ‘mix and match’ the Pfizer and AstraZeneca vaccines? Researchers will ask for 820 volunteers, all over 50 years old, who will be given two shots of a vaccine, two weeks apart. Some will receive AstraZeneca followed by Pfizer, some the other way around and some — the control group — will be given two doses of the same vaccine. Britain has set itself apart from the EU, not just in the speed and extent of its vaccine procurement programme but also for its willingness to experiment. For