The herpes zoster vaccine continues to be effective in protecting older adults against shingles, even after they undergo chemotherapy, according to a Kaiser Permanente study published in the journal Clinical Infectious Diseases.
Researchers examined the electronic health records of more than 21,000 Kaiser Permanente patients in Southern California who were 60 years of age and older and received chemotherapy between January 2007 and December 2012.
Researchers found that those patients who were previously vaccinated with zoster vaccine were 42 percent less likely to develop shingles following chemotherapy. In addition, no vaccinated patients underwent hospitalization for shingles, while six unvaccinated patients were hospitalized with the disease, according to the study.
"The zoster vaccine has been shown to be safe and effective in elderly adults with healthy immune systems but until now, there has been a lack of data on whether the vaccine remains safe and effective for individuals who might have compromised immune systems resulting from treatments like chemotherapy," said study lead author Hung Fu Tseng, PhD, MPH, of the Kaiser Permanente Southern California Department of Research & Evaluation. "Our study demonstrates that older patients who had previously been vaccinated against shingles have a lower chance of developing this painful and often debilitating disease after chemotherapy."
Shingles is caused by the varicella zoster virus and can affect anyone who has had chickenpox. Symptoms of shingles include a painful rash and blisters that develop on one side of the face or body as well as fever, headache and chills. According to the Centers for Disease Control and Prevention, before the zoster vaccine was available, almost one out of every three people in the United States would develop shingles at some point in their lifetime, which translated into more than 1 million cases of shingles expected each year in the U.S.
The risk of developing shingles also increases among those receiving treatments that weaken the immune system, such as chemotherapy for cancers. The lifetime risk of developing cancer is nearly 40 percent among 60-year-old adults, according to the National Cancer Institute. The CDC recommends that people aged 60 years and older get one dose of the zoster vaccine as this is the only way to reduce the risk of developing shingles and prevent long-term complications.
"Age is associated with increased risk of cancers and other medical conditions that may require immunocompromising treatments such as chemotherapy," said Tseng. "It is important that elderly patients get vaccinated when they are relatively healthy, or before starting immunocompromising treatments, because the vaccine isn't advised for those who have weakened immune systems."