Mr. Speaker, in response to (a) to (r), the health and safety of Canadians are Health Canada’s top priority. The department exercises stringent regulatory oversight over vaccines, and conducts a rigorous scientific review of their safety, efficacy and quality prior to authorization. In July 2023, Health Canada evaluated the presence of the SV40 promoter/enhancer sequence in the plasmid used to prepare the Pfizer-BioNTech COVID-19 vaccine, or COMIRNATY, as well as in residual DNA as a manufacturing impurity in the final vaccine product. Clarification requests are routinely issued during submission review to seek clarifications on various aspects of the file. Health Canada submitted a clarification request to Pfizer seeking additional information related to the SV40 sequences. Pfizer provided a reply to address all of Health Canada’s questions. Please note that communications between Health Canada and manufacturers related to the manufacturing and control of a vaccine are considered confidential business information that cannot be disclosed.
The residual plasmid DNA levels measured by the manufacturer, using approved validated methods, were provided to Health Canada and was consistently below the limit of 10 nanograms per human dose. In addition, all COMIRNATY commercial vaccine batches, released in Canada, complied with the quality requirements approved by Health Canada, including the requirements for residual DNA. An Issue Analysis Summary, or IAS, was initially considered to document the process but was later deemed to be unnecessary as the residual DNA content in the final product was consistently below the limit of 10 nanograms per human dose, which is in line with the World Health Organization’s recommendation concerning residual DNA in biological drugs.
The presence of residual plasmid DNA in the mRNA COVID-19 vaccines is considered a manufacturing impurity and does not change the safety assessment of these vaccines by Health Canada.