While influenza vaccine effectiveness declines as the level of frailty increases in older adults, that does not appear to be the case with the adjuvanted recombinant zoster vaccine.

In fact, a report in Human Vaccines & Immunotherapeutics pointed out that high RZV effectiveness was maintained in adults with six or more common selected conditions.

“This further underscores the ability of RZV to induce robust protection against HZ in older adults with multiple medical conditions,” write industry researchers and colleagues.

Patient after receiving vaccine. Source: Getty

The article noted that RZV demonstrated greater than 90% efficacy against herpes zoster in two pivotal efficacy studies -- ZOE-50 and ZOE-70. In those trials, adults 50 or older or those 70 or older were randomized to receive 2 doses of RZV or placebo 2 months apart.  

The post-hoc analysis suggested that RZV efficacy remains high in all selected medical conditions, as well as with increasing number of medical conditions. No safety concern was identified by the type or number of medical conditions present at enrollment.

Medical conditions in order of decreasing frequency included hypertension, osteoarthritis and vertebral disorders, and dyslipidemia. 

Depression and asthma were the most frequently reported conditions known to increase HZ risk included in the analysis. Other medical conditions previously identified as increasing the risk of HZ include systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease, chronic obstructive pulmonary disease, chronic kidney disease, renal failure, hypertension, diabetes mellitus (predominantly type I), and spinal disc herniation, according to the report. 

“The increase in HZ risk associated with some of these conditions may result from the immunosuppressive therapy prescribed to treat the disease and/or from underlying cell-mediated immunosuppression associated with the disease,” study authors wrote.

Results indicated that vaccine efficacy against HZ ranged from 84.5% (95% CI, 46.4–97.1) in participants with respiratory disorders to 97% (95% CI, 82.3–99.9) in those with coronary heart disease at enrollment.

For example, efficacy was 88.8% (95% CI, 63.6–97.8) in participants with asthma, and 91.2% (95% CI, 81.1–96.6) in those with diabetes. 

Researchers reported that the only medical condition where RZV efficacy did not achieve statistical significance was renal disorders (VE: 86.6%; 95% CI, −4.5 to 99.7), adding that the low number of participants with this condition limited the statistical power to assess VE. 

“Overall, RZV efficacy was >90% irrespective of the number of the selected medical conditions reported at enrollment by a participant,” they asserted.

The authors also noted that more than 80% of the overall ZOE-50 and ZOE-70 study population reported at least 1 of the specified conditions. Other studies have shown that RZV also confers strong protection against HZ in immunocompromised populations who are at highest HZ risk, such as hematopoietic stem cell transplant recipients and patients with hematological malignancies. 

No vaccine-related safety concerns were identified in participants with any type or number of the selected medical conditions, the study added.

“In summary, this study showed that >80% of participants had at least 1 of the 15 selected medical conditions present at enrollment. As indicated by the similarity of the point estimates, this post-hoc analysis suggests that RZV efficacy remains high in all selected medical conditions, as well as with increasing number of medical conditions,” the authors concluded. “Point estimates for efficacy ranged between 84.5–97% according to the type of the selected medical conditions (with overlapping 95% confidence intervals) and were >90% even among participants reporting at least 6 of these at enrollment. No safety concern was identified in adults ≥50 YOA presenting these medical conditions.”