Milk allergy tied to rare childhood vaccine anaphylaxis
Last Updated: 2011-06-21 17:05:29 -0400 (Reuters Health)
By David Douglas
NEW YORK (Reuters Health) - Very rarely, residual casein in vaccines against tetanus, diphtheria, and pertussis may provoke anaphylaxis, according to a recent report.
"Our report strongly suggests that trace residual milk protein in the vaccine can trigger an allergic reaction in extremely sensitive milk-allergic children," Dr. Scott H. Sicherer told Reuters Health by email. "However, the vast majority of children with milk allergy, even those with significant milk allergy, have no reactions to the vaccine."
Anaphylactic reactions to these vaccines are rare and are generally attributed to the vaccine toxoids, said Dr. Sicherer and colleagues in a May 30th letter to the editor of the Journal of Allergy and Clinical Immunology.
They note that the US national Vaccine Adverse Events Reporting System lists 39 anaphylactic reactions to DTaP, DTP, or Tdap vaccines in children between 2007 and 2010.
During this period, eight children at their center had symptoms of anaphylaxis within an hour after receiving booster doses of these vaccines.
To investigate whether residual casein from cow's milk might be involved, the researchers examined the childrens' records and found that six had prior acute allergic reactions to cow's milk. The remaining two patients had been given a diagnosis of milk allergy based on serologic testing.
Each of the patients had an increased milk-specific IgE level documented within two years of the reaction to the vaccine.
The investigators went on to test Tdap and DTaP vaccines and "identified casein in eight lots of the vaccines, raising the concern that residual casein in the vaccines might result in reactions for highly sensitive patients."
Nevertheless, the authors say they "cannot accurately define a high-risk group based on this case series. Clearly, many highly sensitive children with milk allergy tolerate the vaccines because these reactions are apparently rare."
"Our job now is to try to confirm our observation, and learn how to identify those at risk where the vaccine would be given with additional caution," Dr. Sicherer said.
One of the researchers owns 45% of Herbal Springs, a company that makes herbal treatments for asthma.
SOURCE:http://bit.ly/jfzwiS
J Allergy Clin Immunol 2011.
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