(Reuters) -Canada on Friday authorised updated COVID-19 booster shots from Pfizer Inc and its partner BioNTech SE that target the Omicron BA.4 and BA.5 subvariants, according to the government’s website. Pfizer and BioNTech said in a joint statement the companies will make “significant volumes of the vaccine available in the coming days”. The booster shot, which has been authorised for people 12 years and older, is the second to get clearance from Health Canada after Moderna Inc’s modified booster last month. Moderna’s vaccine booster was cleared for use in adults. The so-called bivalent vacci…