Covid-19 vaccine.It comes as experts raise fears over how much protection will be provided if different jabs are mixed. NHS Greater Glasgow and Clyde (NHSGGC) – which serves about 1.2million people – said “every effort” will be made to provide the same pharma brand but added: “There is the ability to administer a different vaccine if that is not possible.” It means those given a first shot of Pfizer’s drug could receive a second of the AstraZeneca compound – despite there being no data on the level of immunity provided from blending the injections.