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| Herpes zoster can cause shingles, a painful condition with serious complications |
Herpes zoster is a common virus, affecting a million Americans each year, with potentially serious consequences.
The virus causes both chicken pox and shingles. Following chickenpox, the virus remains inactive, or dormant, within the body.
If it becomes active again, which can be after many years, it can cause shingles, a painful, blistering skin rash that can be complicated by prolonged, severe, disabling pain - a condition called post-herpetic neuralgia (PHN).
Shingles can appear at any age but particularly in people over 60, those who had chickenpox before the age of 1 year, or individuals with a weakened immune system.
A person who has direct contact with the shingles rash and has not previously had either chickenpox or the vaccine can develop chickenpox but not shingles. However, chickenpox can be so mild that people do not notice it at the time; they may later develop shingles.
It is not yet clear why the virus suddenly becomes active again.
Increased cardiovascular risk after herpes zoster
Acute cardiovascular diseases (CVDs), including ischemic stroke and myocardial infarction (MI), are major causes of morbidity and mortality in the US. A better understanding is needed of what causes acute CVDs and how they can be prevented.Acute infections are thought to lead to CVDs because of dysfunction within the blood vessels, in which plaques rupture in the artery wall, increasing the risk of blood clots.
In 2006, a targeted vaccination program for those aged 60 years or older was introduced in the US in an effort to prevent zoster-associated morbidity.
Caroline Minassian and colleagues from the London School of Hygiene and Tropical Medicine in the UK wanted to measure the short-term increased risk of stroke and MI after zoster, as well as the impact of zoster vaccination.
The team identified 42,954 Medicare beneficiaries aged 65 years and over who had a herpes zoster diagnosis and an ischemic stroke, and 24,237 beneficiaries who had a herpes zoster diagnosis and MI during a 5-year period.
The researchers then calculated the chance of having stroke or MI within 12 months of a zoster diagnosis, compared with times when the patient did not have the virus, known as the baseline period. They also adjusted for age.
Among those diagnosed with herpes zoster within the past year, there was a 2.4-times higher chance of an ischemic stroke and 1.7 times higher chance of MI in the first week after herpes zoster, compared with the baseline period. The risk decreased gradually over the 6 months following the herpes zoster diagnosis.
Ischemic stroke and MI incidence ratios appeared to be the same regardless of whether individuals had been vaccinated against zoster or not.
Limitations include the fact that major life events and stress were not taken into account, and that only a few participants had been vaccinated, thus reducing the ability to detect the effect of vaccination.
The authors say:
"These findings enhance our understanding of the temporality and magnitude of the association between zoster and acute cardiovascular events."A previous study published by Medical News Today suggests that a higher rate of stroke is linked to shingles.
