Vaccine batch 'put on hold' in Canada
Canada, like the UK is one of many countries worldwide using the Pandemrix swine flu vaccine.
Now Canadian health officials and the manufacturers GlaxoSmithKline have asked doctors to stop using a single batch of 172,000 doses.
It comes after six people apparently experienced severe allergic reactions - which might include breathing problems, raised heart rate and skin rashes.
GSK is investigating the reports - this may result in the withdrawal of the batch. It's reported that one in 20,000 people suffered reactions to this batch - five times the expected number.
None suffered long term ill effects. The vaccination programme in Canada is continuing, using other supplies of Pandemrix.
A spokeswoman for GSK Gwenan White said that 7.5 million doses of Pandemrix had been distributed in Canada and the action taken over the batch was a purely precautionary measure. "It may well be that after further investigation, the batch can be used" she said.
Canada's doses are produced at a manufacturing plant in Quebec. None of the stocks of vaccine bound for the UK are affected - all produced at a plant in Dresden, Germany.
Only yesterday GSK announced that more than 40 million doses of Pandemrix had been distributed globally - something it revealed first in this blog a week ago.
GSK also announced results from a clinical trial among children which showed a strong immune response from one dose of Pandemrix.
Update, 08:58, Wednesday 25 November: I've received this statement from Geoffrey Matthews at the Public Health Agency of Canada about Arepanrix which is the Canadian name for Pandemrix:
"The Public Health Agency of Canada, is reviewing reports of a higher than normal number of adverse events associated with one particular lot of the H1N1 flu vaccine that was distributed over the week of November 2, 2009.
"As a precautionary step, on November 18 Health Canada asked GSK to instruct provinces who have received adjuvanted GSK vaccine Arepanrix doses from Lot 7A ( BC, AB, SK, NB, ON, PEI) not to use any remaining doses of that lot for vaccination.
"This will allow Health Canada, GSK, the Public Health Agency of Canada and the relevant jurisdictions to investigate the cause of the higher than expected number of allergic reactions to the vaccine in persons immunized with that Lot.
"Placing vaccine lots on hold is not an unusual occurrence. Over the past few years, Health Canada has placed specific lots of other vaccine on hold pending further investigation.
"A total of six adverse events (all analyphlaxis) associated with this lot have been reported (the lot in question comprises 172,000 doses). All six individuals who experienced severe allergic reactions have fully recovered.
"Anaphylaxis is a severe allergic reaction that is readily treatable, but can be life-threatening. Therefore it is considered a serious adverse event.
"The Public Health Agency of Canada, Health Canada (the regulator) and the provinces and territories have been working together, and with Canada's vaccine manufacturer, to ensure that all adverse events are reported and assessed.
"People who have received the vaccine and have not had an allergic reaction, have no reason to be concerned.
"The H1N1 flu virus vaccine has proven to be both safe and highly effective. The fact that we have identified a potential safety issue underscores that our monitoring system works."