The H1N1 vaccine that seemed frought with controversy from the beginning has hit a new snag. When initial production time estimates ended up being faster than what was actually possible the public wondered whether there would be enough? Would the vaccine be effective? Was it safe? Would there be enough health workers to dispense on pace with demand? Would vulnerable populations get priority over others?
Tuesday, 800,000 pediatric doses of the vaccine were recalled due to potency issues. Certain doses intended for children 6 to 35 months old are apparently not strong enough to do the job. According to the Department of Health and Mental Hygiene deputy secretary Fran Phillips, "This is not a safety concern, rather a question of whether or not as strong a potency as they needed to be," she said of the recalled doses. The CDC also describes the issue as "non-safety-related".
The manufacturers of the voluntarily recalled doses, Sarnofi Pasteur, discovered that the potency in one particular lot of pediatric syringes had diminished since it was produced. Further testing identified three other lots of weakened vaccine doses.
The CDC recommended a two-vaccine protocol for children initially, and health officials say that children under 10 that were vaccinated with the weaker doses should continue through the protocol and get the second shot, however they need not repeat the first vaccine. All unused doses of the weaker vaccine are being removed from public inventory and returned to the manufacturer. The problem appears to be confined to 0.25 ml pre-filled syringes in 10- and 25-packs. Multi dose vials and single-dose 0.5-ml pre-filled syringes for persons 36 months and older are not affected. The nasal sprays are also not affected.
The lot numbers affected by the recall can be found on this CDC web page.