Shingles, or herpes zoster, is a common infection of the nerves, which is caused by a virus. It triggers a painful rash or small blisters on an area of skin. Shingles is caused when the chickenpox virus is reactivated. After a person has had chickenpox, the virus lies dormant in certain nerves for many years. Shingles is more common in people with weakened immune systems, and in people over the age of 50. In addition to causing pain, a new study has found that herpes zoster is associated with an increased risk of cardiovascular disease: heart attacks and stroke. The findings were published in the journal PLOS Medicine by researchers at the Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, United Kingdom; and the Department of Health Services and Population Research, Kings College London, London, United Kingdom.
The study authors note that herpes zoster infections are common and can have serious consequences. In addition, recent data has suggested an increased risk of acute cardiovascular events following herpes zoster. However, to the best of their knowledge, existing studies compare outcomes between individuals; thus, they are vulnerable to between-person confounding factors (factors that can skew the data). Therefore, they conducted a study with a within-person design to measure any short-term increased risk of acute cardiovascular events (stroke and myocardial infarction [MI]) after a herpes zoster infection and to determine whether zoster vaccination modifies this association.
The study group comprised Medicare beneficiaries aged 65 years or older with a herpes zoster diagnosis and either an ischemic stroke (42,954 individuals) or MI (24,237 individuals) from January 1, 2006 through 31 December 31, 2011. The researchers found a significant increase in the rate of acute cardiovascular events in the first week after a herpes zoster diagnosis: a 2.4-fold increased ischemic stroke rate, and a 1.7-fold increased MI rate, followed by a gradual resolution over six months. Herpes zoster vaccination did not appear to modify the association with MI. They also found no evidence for a difference in the risk for ischemic stroke between vaccinated and unvaccinated individuals during the first four weeks after a herpes zoster diagnosis; however, the relatively few vaccinated individuals limited the study’s ability to assess the role of vaccination.
The authors concluded that stroke and MI rates are transiently increased after exposure to herpes zoster. However, they found no evidence for a role of herpes zoster vaccination in these associations. They noted that their findings enhance understanding of the temporality and magnitude of the association between zoster and acute cardiovascular events.
Take home message:
Inasmuch as only a small number of the subjects had received a herpes zoster vaccination, it is possible that being vaccinated can reduce the risk of a cardiovascular event. Also, vaccination can prevent the infection. The herpes zoster virus can lie dormant for decades and flare up after exposure to an individual with chickenpox. Thus, it is prudent to avoid contact with children with chickenpox
