The recent rise in pertussis rates may have peaked, but the experts are responding by reinstating a working group.
The new working group for pertussis was announced at a meeting of the Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices. The ACIP’s new group, led by Fiona Havers, MD, of the CDC, heard data on the currently available pertussis vaccines and solicited ideas from ACIP members about what other data they would like before the February meeting.
One question on the agenda is whether the current recommendation that nonpregnant adults receive a single lifetime dose of Tdap and then tetanus-diphtheria (Td) boosters every 10 years be expanded to allow either Tdap or Td as the booster. Reasons for considering the change include possible changes in the circulating pertussis strain, improved diagnosis and reporting, and the waning of protection under the current guidelines, as well as the potential economic impact, Dr. Havers said.
This change could make booster administration easier for many physicians who do not routinely stock Td, some committee members noted. In addition, the Food and Drug Administration has approved a label change for one Tdap manufacturer to remove “single use” language.
In a study presented by David P. Greenberg, MD, associate vice president of Sanofi Pasteur, seroprotection rates to tetanus and diphtheria were similar in a comparison between groups of adults aged 18 years and older, receiving either Tdap (Adacel) or Td as a booster. “Seroprotection was greater than 99% in both groups,” he said.
Pain was the most common injection site reaction in both groups, rates of serious adverse events were similarly low (0.8% and 0.3%, respectively), and no deaths occurred in patients given either vaccine.
The postvaccination antipertussis geometric mean concentrations were noninferior in the Tdap group, compared with the Td group, Dr. Greenberg said.
A phase III open label study presented by Leonard Silverstein, MD, of GlaxoSmithKline also showed similar seroprotection rates for adults revaccinated with Tdap after an initial vaccination with either of two different Tdap vaccines.
Also at the February meeting, the committee will address whether any vaccine that contained Td should be allowed for use as tetanus prophylaxis in the setting of wound management, said Dr. Havers.
The committee members expressed interest in more information on several topics including pregnancy and pertussis, whether manufacturers could discuss vaccines in the pipeline, data on responses to multiple doses and if there is a point of diminishing returns, and whether some states are covering Tdap for adults.
The committee members had no financial conflicts to disclose.