British pharma giant AstraZeneca has admitted that its Covid vaccine can cause rare side effects, The Telegraph (UK) has reported. Covishield can cause, in rare cases, a condition that leads to blood clots and low platelet count, the vaccine-maker has said in court documents. Covishield, developed by AstraZeneca and Oxford University during the pandemic, was produced by the Serum Institute of India and widely administered in the country.