To the Editor Le and Rothberg1 recently assessed the cost-effectiveness of the adjuvanted herpes zoster subunit vaccine in a population of older adults, finding that it was cost-effective at the commonly accepted willingness-to-pay threshold of $50 000 per quality-adjusted life-year. In their analyses, the authors accounted for not only the costs of the vaccine and the benefits associated with the prevention of herpes zoster but also the costs and decreased quality of life associated with adverse effects.1 In an accompanying editorial, Najafzadeh2 discussed the evolution and value of the herpes zoster vaccine. However, in this piece, Najafzadeh stated that there were no significant safety concerns associated with the live attenuated vaccine in the Shingles Prevention Study (SPS).3 On the contrary, the SPS had a substudy designed to prospectively evaluate adverse events, and found a significant increase in the occurrence of not only injection-site adverse reactions such as pain, erythema, or swelling in the vaccine group, but also in the incidence of serious adverse events including congestive heart failure and pulmonary edema.4,5 Based on this finding, the FDA requested that the manufacturer conduct a postlicensure study of 12 000 patients to further evaluate serious adverse events associated with the vaccine.4 Although subsequent investigations did not confirm safety issues, it is important to recognize the possibility of adverse events with any vaccination, as Le and Rothberg did in their analyses, and to place those risks within the context of known benefits of vaccination. For most if not all vaccines the benefits far outweigh risks (as is the case with the zoster vaccine), but given concerns of a vocal minority who question vaccine safety, the medical community must not misstate evidence of potential harm.