Following reports from Canada's Public Health Agency that six patients had suffered allergic reactions after receiving the shot, GlaxoSmithKline plc (NYSE:GSK) (Middlesex, England) has voluntarily placed a hold on a single batch of the AS03 adjuvanted H1N1 vaccine Arepanrix in Canada as a precautionary measure. The batch comprised 172,000 doses of the drug and had been distributed to health agencies in the provinces of Alberta, British Columbia, Manitoba, Ontario, Prince Edward Island and Saskatchewan.