ATLANTA — Questions about varicella immunity and human papillomavirus vaccine logistics topped physicians' concerns during a Q&A session with an expert panel at the annual National Immunization Conference sponsored by the Centers for Disease Control and Prevention.
The panelists included Dr. William Atkinson, Dr. Andrew Kroger, and Donna Weaver, R.N., of the CDC's National Center for Immunization and Respiratory Diseases.
Among the questions were the following:
Does an infant less than 1 year old who develops chickenpox still need the varicella vaccine?
"A few experts will say if you are absolutely sure it was chickenpox ... the child would have natural immunity in that circumstance and not need another dose," Dr. Kroger said. But it can be difficult to be certain. He advised clinicians to "play it safe" and follow the recommended ages for vaccination. A dose of the varicella vaccine won't hurt a child who had chickenpox as an infant, he said.
Is birth prior to 1980 evidence of varicella immunity?
Dr. Atkinson said that for health care workers and pregnant women, being born before 1980 is not considered evidence of varicella immunity. The CDC's Advisory Committee on Immunization Practices has a document forthcoming on health care workers later this year, he added.
When a private clinic sees teens who have begun their human papillomavirus (HPV) vaccine series elsewhere, can the series be finished with a vaccine different from the one with which they started the series?
Both the quadrivalent HPV vaccine Gardasil and the bivalent HPV vaccine Cervarix protect against HPV serotypes 16 and 18, but only Gardasil protects against HPV-6 and -11 as well. Ideally, said Ms. Weaver, you should use the same vaccine you started with. If you have to switch, you need to make it clear that there's no protection for HPV-6 and -11 if you're not using Gardasil. "It's preferred that you complete the series with the same vaccine if you can," she said.
Would the male HPV vaccine help protect females?
"The hope is certainly there, but ... we don't know at this point," said Ms. Weaver.
"That would be a very tough study to do," Dr. Atkinson observed. "What kind of study would you design ... to be able to show that transmission was less frequent from—or to—a vaccinated person compared to an unvaccinated person?"
Generally, immune people don't transmit and don't get infected, he reminded the audience, "so it's reasonable to hope ... that it will interfere with transmission."
None of the panelists reported any conflicts of interest.