Tdap comparable to Td vaccine, recommended for older adults

Gregory A. Poland, MD, MACP, FIDSA

Tseng et al have published an important article on the safety of the Tdap vaccine used off-label in elderly patients. The article is important because it reassures both providers and patients that the use of this vaccine is safe when used in the elderly. 

Tseng et al reported on a matched cohort study (MCS) of 119,573 adults aged at least 65 years who received the Tdap vaccine and the same number who received the Td vaccine. They demonstrated that the risk of prespecified events (meningitis, encephalitis, encephalopathy, cranial nerve disorders, Bell’s palsy, Guillain-Barré syndrome, brachial neuritis, paralytic syndromes, medically attended inflammatory or allergic events, and anaphylaxis and generalized reactions) were no different in Tdap vs. Td recipients. In a second analysis, using a self-controlled case series (SCCS; ie, each subject was studied for vaccine side effects for a prespecified length of time after vaccine receipt, and then again in a second time period of equal duration), no increase in prespecified events occurred with the exception of an increased rate (incidence rate ratio=1.59) of “medically attended inflammatory or allergic events” in the first 6 days following Tdap — as expected. While medical records were not reviewed in the SCCS analysis, they were in the MCS analysis, and this revealed that the “medically attended inflammatory or allergic events” did not include any anaphylaxis cases, and otherwise were fever or “generalized reactions” (n=2 for Tdap and n=1 for Td).

Readers are likely aware that in July 2011, Tdap (Boostrix, GlaxoSmithKline) was licensed for use in persons aged 65 years or older. However, the Advisory Committee on Immunization Practices recommended the use of Tdap vaccine in persons aged 65 years or older in 2010 — before the vaccine was licensed for use in this age group. This recommendation was made with little data in regards to the safety of immunizing this age group, but was considered important to do, given that the US was in a time period when pertussis outbreaks were widespread, cases were increasing dramatically, and deaths among very young children were increasing. The report of Tseng et al reassure us that such a recommendation, while necessary for both individual and the public’s health, is also safe.

The bottom line — in an era where the number of documented cases of pertussis in the United States is at an all-time 60-year high, and for a disease that has significant morbidity and mortality (for young children), and where the disease itself is non-immunizing; providers must understand the necessity of inquiring, recommending and providing Tdap vaccine to their older patients aged 65 years and older. Adults, after all, are the reservoir of disease, and these data confirm the safety of the vaccine in this age group. While better vaccines are needed that provide a longer duration of immunity, current vaccines, if used at high rates in the population, are highly beneficial in protecting the public health — especially our children. Concerns about Tdap vaccine safety should never be a reason to not immunize.