Canadian border guards discovered 328 suspect vaccines in a traveller’s luggage at Vancouver airport in May, prompting investigations by the Canadian public health agency.
Despite months of testing and investigations, many of these vaccines remained uncertified, a spokeswoman for Public Health Agency of Canada (PHAC) told the BBC on Tuesday.
Although some should be disposed of, Ms Naomi Kortze told the BBC, much of this literature, which is in the possession of several international health agencies, has been destroyed.
Vaccines can be certified for sale in Canada and approved by health officials for use in the population. Tests have been carried out by PHAC to verify that all the 18 imported specimens that were tested were for “national vaccination needs”, the agency’s spokesperson added.
But the cost of completing these tests can be prohibitive for private clinics.
Preferably, the carrier of the virus should be identified for clinical testing before it arrives, a Hong Kong-based infectious disease expert told BBC.
Only a small percentage of the vaccines were considered legitimate, Philip Cunningham, who retired from PHAC in 2011, added.
“A lot of the vaccines in question were pulled at the airport,” Professor Cunningham told the BBC. “They were basically given to clients by owners or suppliers, and it was just an insurance policy they were taking to protect themselves if something went wrong”.
Private clinics typically acquire vaccines from online sources or by contacting suppliers who were recently accredited, and they are unable to say how many vaccines were withdrawn.
Before it is shipped, a vaccine is typically given to a set number of pet owners, or others who have previously bought it and keep it. The clinics then sell the vaccine via the internet for $4,000-6,000 (about £3,500-4,300) and it is likely to make at least a small profit.
Who else was affected?
Although the vast majority of suspicious vaccines turned out to be harmless, seven packs of human papillomavirus (HPV) vaccine were also detected.
HPV is one of the most common sexually transmitted infections in the world, and is responsible for more than 70% of new cervical cancer cases. A vaccine against the virus has been available in Canada since 2011, but there is currently no government legislation requiring vaccinations in the country, although officials believe it may come in future.
Prof Cunningham said PHAC had “not had a tonne of trouble with [the] HPV vaccine” in Canada, but additional testing of vaccines was conducted on four of them. HPV vaccines produced by the WHO have a certificate issued by a manufacturer in accordance with WHO standards and require proof that it has been given to a user in compliance with those standards, an official told the BBC.
The four vaccines from the shipment were also withdrawn from the public health system, she added.
Although Canada does not officially endorse or require vaccination, the country does support vaccination for public health reasons.
More than 50 other countries include HPV vaccine in their vaccination schedules and U.S officials say vaccines against HPV-related cancers should be on tap for every U.S. citizen, given the significant public health gains achieved by vaccinating populations with the human papillomavirus.