(Reuters) - The UK drug regulator added an extremely rare nerve-damaging disorder, Guillain-Barré syndrome (GBS), as a very rare side effect of the AstraZeneca COVID-19 vaccine, updates on the agency’s website showed on Thursday. Medicines and Healthcare products Regulatory Agency’s (MHRA) decision comes after the European medicines agency added GBS as a possible side-effect last month. Reporting by Yadarisa Shabong in Bengaluru; Editing by Shinjini Ganguli