By Reuters Staff 1 Min Read FILE PHOTO: European Commission President Ursula von der Leyen speaks at the signing ceremony of the declaration on the Future of Europe, in Brussels, Belgium March 10, 2021. REUTERS/Johanna Geron/Pool BRUSSELS (Reuters) - Britain needs to show a willingness to ship vaccines to the European Union, which is considering making reciprocity a condition of its vaccine exports in future, the head of the European Commission said on Wednesday. Ursula von der Leyen said it was hard to explain to EU citizens why vaccines were going to other countries, while hardly anything was heading the other way.