Canada’s drug regulator asked Pfizer to provide data on the size of DNA fragments in its COVID-19 vaccine, due to genomic integration concerns, shortly after learning the pharma giant withheld information on DNA sequences contained in its product.“Concerning the residual plasmid DNA in the drug substance, provide data/information characterizing [...] the size distribution of the residual DNA fragments [and] residual intact circular plasmid,” says a request for clarification Health Canada issued to Pfizer on Aug. 4, 2023.A sign is displayed in front of Health Canada headquarters in Ottawa in a file photo. (Sean Kilpatrick/The Canadian Press)The information was released as...