By Reuters Staff 2 Min Read FILE PHOTO: A vial of the Oxford-AstraZeneca COVID-19 vaccine is pictured at Basingstoke Fire Station, in Basingstoke, Britain February 4, 2021. REUTERS/Peter Cziborra LONDON (Reuters) - Data from Britain’s vaccine rollout on the effectiveness of the AstraZeneca/Oxford University COVID-19 shot in older people should help other countries reassess their use of it, the head of the university’s vaccine research group said on Tuesday. Britain has been rolling out the vaccine since January, beginning with the elderly and health workers, after approving its use for all adults. Many European countries have advised that the vaccine should not be given to over-65s due to a lack of clinical trial data on its efficacy in that age group, and a significant proportion of doses of the vaccine that they have acquired have gone unused.