MIAMI BEACH — Inadvertent misadministration can occur with several new vaccines that are commonly used, Dr. Larry Pickering said at the annual Masters of Pediatrics conference sponsored by the University of Miami.
One potential source of confusion involves the two new tetanus toxoid, diphtheria toxoid, and acellular pertussis (Tdap) vaccines licensed in 2005 for adolescents and adults, and the diphtheria, tetanus, and pertussis (DTaP) vaccine licensed in 1991 for children 6 weeks to 6 years of age.
One of the reasons for the confusion is that the labeling and packaging are very similar for Adacel (Tdap) and Daptacel (DTaP), Dr. Pickering said.
Sanofi Pasteur, maker of Adacel and Daptacel, confirms it has received reports of misadministration, more commonly involving adults being given the pediatric formulation, Donna K. Cary, director of public relations for Sanofi, said in an interview.
“For many years, DTaP was just a pediatric product, and it wasn't until just recently that we had Adacel for adults and adolescents, and GlaxoSmithKline has Boostrix,” Ms. Cary said. “I think it's that there is a new vaccine. The packaging is actually quite different.”
The company has started tracking reports of misadministration and is looking at ways to make the two products more distinct, such as noting on the label that Daptacel is for infants, she said. The Adacel label already states it is for adolescents and adults.
Until such changes are made, Dr. Pickering said, he keeps the two vaccines straight in his mind by remembering that Adacel and adult both begin with the letter A.
Dr. Pickering is unaware of any reports of mix-ups occurring with GlaxoSmithKline's Boostrix (Tdap) and Infanrix (DTaP) vaccines. No reports of misadministration of its products have been reported to GlaxoSmithKline, spokeswoman Liad Diamond said in an interview.
If an adolescent or adult inadvertently receives DTaP, the vaccine doesn't have to be repeated, although the patient may have increased reactions because the antigen contents are higher, Dr. Pickering said. If Tdap is given to an infant or child, the antigen contents are much lower and the dose will have to be repeated.
A second kind of vaccine mix-up has been reported involving the meningococcal polysaccharide vaccine that has been used subcutaneously for decades in the United States. The newer tetravalent meningococcal conjugate (MCV4) vaccine, licensed in the United States in January 2005, is for intramuscular use only.
The different routes of administration create an “automatic opportunity for confusion,” said Dr. Pickering, professor of pediatrics at Emory University and senior advisor to the director of the National Center for Immunization and Respiratory Diseases at the Centers for Disease Control and Prevention, both in Atlanta.
Indeed, 101 people in seven states have reportedly received subcutaneous administration of the MCV4 vaccine, according to an investigation by the CDC (MMWR 2006;55:1016–17).
There were 12 nonserious adverse events, including 11 local reactions and a report of fever for 1 day among 54 people queried by providers as a result of the investigation. Serology results from 38 people vaccinated by the subcutaneous route indicate that although their titers were lower than those of patients vaccinated by the intramuscular route, the subcutaneously vaccinated patients were sufficiently protected and didn't need revaccination.
Finally, the Advisory Committee on Immunization Practices recently received reports of adults accidentally receiving the new adult zoster (Varivax) vaccine used to prevent the varicella zoster virus in patients 12 months of age and older, and of infants receiving the Zostavax vaccine used to prevent herpes zoster in adults 60 years of age or older.
Even though all varicella products are made from the same varicella-zoster bulk lots, the zoster vaccine concentration is 14 times higher than the varicella vaccine concentration, Dr. Pickering noted.
If the varicella vaccine is given to an adult, it might not work because of the lower vaccine content, he said. In case of such a mix-up, an adult should then receive the correct zoster vaccine.
If zoster vaccine is inadvertently given to a small child, the dose should count, but reactions might be greater and could include local skin reactions, low-grade fever, and the development of vesicular lesions around the injection site.