By: Dr. Geoffrey Modest
The Shingles Prevention Study (SPS) initially demonstrated efficacy of the zoster vaccine for 4 years. The Long-Term Persistance Substudy (LTPS), however, has shown marked decrease efficacy after about 8 years (see doi: 10.1093/cid/ciu918).
Details:
–6867 SPS vaccine recipients were enrolled in LTPS: 97.8% white, 56.3% men, median age 74.5 with 20.8% older than 80
–estimated vaccine efficacy decreased in LTPS over the initial SPS values (4 year data) from 61.1% to 37.3% for the burden of illness (BOI, a measure of the severity-by-duration of zoster pain and discomfort), from 66.5% to 35.4% for the incidence of postherpetic neuralgia and from 51.3% to 21.1% for the incidence of clinical zoster itself.
–statistically, vaccine efficacy for BOI was still significant after 10 years post-vaccination, but for clinical zoster it was only significant for 8 years
–no additional vaccine-related adverse events in the LTPS over what was reported in SPS
–of note, there was no control population for the LTPS study, just historical controls, based on the placebo groups in SPS
So, I’m really not sure where we are going with some of these vaccines. I have posted previous blogs about the apparently quite short (3-4 year) efficacy of the pertussis component of Tdap in adults, given the high frequency of reported pertussis outbreaks even in those recently immunized (though it is recommended only once in adulthood specifically for the pertussis component). And now the pretty limited efficacy of the zoster vaccine. We will see what the CDC is going to recommend…..