When administered at the same time, patients may misattribute adverse effects of the recombinant zoster vaccine to the flu vaccine.
Patients who receive the recombinant zoster and flu vaccines simultaneously were less likely to receive the flu vaccine the following year, according to study results published in JAMA Network Open1
According to researchers, 1 explanation may be that patients incorrectly attribute adverse effects from the recombinant zoster vaccine to the flu vaccine, causing some to not get the flu vaccine the following year. The recombinant varicella zoster vaccine for shingles prevention is reactogenic, leading to adverse effects in approximately half of patients who receive it.
It is important to note, however, that “[t]his vaccine hesitancy based on perceived side effects exists despite evidence that rates of systemic side effects (eg, fatigue, myalgias, headaches, and fever or chills) are comparable among patients receiving the influenza vaccine and those receiving a placebo.”1 Therefore, pharmacists are encouraged to administer the 2 vaccines separately, or to additionally educate patients about possible vaccine adverse effects.
This cohort study included patients aged 50 years or older who received the influenza vaccine between August 1, 2018 and March 31, 2019 who also received the recombinant zoster vaccine on the same day or separately. There were 89,237 patients studied with a median age of 72 years (interquartile range [IQR], 67-77 years). Of the patients included, 58.3% were women, 70.1% were White, and a majority—85.7%—had 1 or more comorbid conditions.
Flu vaccination rates from 2019 to 2020 were lower in the 27,161 patients who received concurrent flu and recombinanat zoster vaccines compared with the 62,076 individuals who received the vaccines on separate days (87.3% vs 91.3%; adjusted odds ratio, 0.74; 95% CI, 0.71-0.78).
If the recombinant zoster vaccine is due at the same time as other routine vaccines, including the yearly flu vaccine, the CDC recommends coadministration. However, given the different reactogenicity of the zoster and flu vaccines, administering the 2 vaccines together may lower the likeliness of patients receiving flu vaccines in the following years.
Study limitations relate to the flu vaccine uptake being much higher than in the general population, suggesting that this study included patients particularly prone to receiving an annual flu vaccine.1
1. Rome BN, Feldman WB, Fischer MA, Desai RJ, Avorn J. Influenza vaccine uptake in the year after concurrent vs separate influenza and zoster immunization. JAMA Netw Open. 2021;4(11):e2135362. doi:10.1001/jamanetworkopen.2021.35362