Denmark will prolong its suspension of AstraZeneca's COVID-19 shots by three weeks pending further investigations into a potential link between the vaccine and rare cases of blood clots.Denmark was among the first countries in Europe this month to suspend the use of AstraZeneca's vaccine after reports of a small number of unusual cases of blood clots, registered both in Denmark and elsewhere."Our basis for making a final decision on the further use of the COVID-19 vaccine by AstraZeneca is too uncertain," director of the Danish Health Authority, Soren Brostrom, said in a statement."Many studies have been launched, but we do not yet have any conclusions.