Shingles and Flu Vaccines: "Is it OK for Me to Get These Shots at the Same Time?"
—Older adults are advised to protect themselves from flu and shingles, but is offering adjuvanted vaccinations for both conditions simultaneously an acceptable option? Expedient, yes. Safe…?
A new study in JAMA Network Open is the first randomized clinical trial in the US to directly compare the safety and reactogenicity after the simultaneous administration of two vaccines containing novel adjuvants, recombinant zoster vaccine (RZV) and adjuvanted quadrivalent formulation (aIIV4), among older adults.
This blinded clinical trial was conducted among community-dwelling adults from two centers during the 2021-2022 and 2022-2023 flu seasons. A total of 267 adults were included with a median age of 71 years; 51.3% were men. These participants were randomized into either the RZV and aIIV4 group or the RZV and quadrivalent high-dose inactivated influenza vaccine (HD-IIV4) group. Vaccines were administered intramuscularly on opposite arms on an intention-to-treat basis.
The investigators watched for severe solicited local or systemic reactogenicity events (grade 3) during days 1 to 8 of the study period, as well as other reactions during days 1 to 43.
Safety in simultaneous vax groups
Ultimately, the postvaccination safety findings were similar between the groups studied. A total of 130 participants received RZV and aIIV4 simultaneously, while 137 received RZV with HD-IIV4. The proportion of participants reporting one or more severe reactions was comparable between those who received RZV and aIIV4 (11.5) and those who received RZV and HD-IIV4 (12.5%) (absolute difference, −1.0% [95% CI, −8.9% to 7.1%]).
“From a safety standpoint, this study supports the simultaneous administration of RZV and aIIV4 among older adults,” the authors reported. In addition, the effect on health-related quality of life (HRQOL) did not differ significantly between the two cohorts.
Were any events immune-mediated?
In general, few participants suffered serious adverse reactions (SAEs) during the trial, and any postvaccination effects were those commonly seen among older adults.
- A total of nine SAEs were seen throughout the study period. (The safety profiles of aIIV4, HD-IIV4, and RZV all aligned with those reported in prelicensure studies for each respective vaccine.)
- Six events occurred within 43 days postvaccination, with one in the RZV and aIIV4 group. However, the distribution of side effects evened out over time: 4 of 130 effects (3.1%) were recorded in the aIIV4 group while 5 of 137 (3.7%) were seen in the HD-IIV4 group.
- Among participants with grade 3 reactions, recovery patterns were also similar in the two cohorts.
Considering the possibility that novel adjuvants could activate immune-mediated disease in some individuals, the authors point out one potentially immune-mediated event in the study. In the HD-IIV4 group, one participant developed a left third cranial nerve palsy 25 days postvaccination, prompting a one-day hospitalization, though the palsy resolved within 8 weeks. None of the other reactions, serious or otherwise, prompted medical visits.
Still, active surveillance is needed
The authors note some limitations of the study which, due to the challenges of COVID-19, did not meet enrollment goals and may have been underpowered. In addition, the proportion of Black and Hispanic populations were small, limiting generalizability. Finally, as with other randomized clinical trials, the population size was too modest to pinpoint rare serious adverse events.
“Vaccine safety active surveillance systems could be used to assess the frequency of rare safety events, including immune-mediated disease, among older adults receiving aIIV and RZV,” they advised.
“From a safety standpoint, this study supports the simultaneous administration of RZV and aIIV4 among older adults,” the authors concluded.
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