(Reuters) -The European Union’s drug regulator on Thursday approved Pfizer Inc’s antiviral COVID-19 pill for treating adults at risk of severe illness, as the region scrambles to boost its arsenal to fight the Omicron variant. The endorsement by the European Medicines Agency (EMA) for a conditional approval, if followed as usual by the European Commission, allows EU member states to deploy the drug after the regulator gave guidance for its emergency use late last year. Italy, Germany and Belgium are among a handful of EU countries that have bought the drug branded as Paxlovid. The United State…