Chickenpox is a common childhood illness, endured by many. While it’s true that in most cases you only get chickenpox once, the virus can revisit many times. If you have contracted chickenpox in the past, it’s possible you have had, or may at some point get, shingles – known by the medical fraternity as herpes zoster (HZ).
Professor Anthony Cunningham, director of the Westmead Millennium Institute in NSW, says, “Herpes zoster is a cousin to the herpes simplex, or cold sore virus. Like herpes simplex, the virus never completely goes away, it hides sneakily in the nerves and can come back at any time depending on your general health.”
Shingles is a skin or mucosal infection caused by the varicella-zoster virus (VZV), the same virus that causes chickenpox. Once an outbreak of chickenpox has occurred the virus lays dormant and establishes latency in the dorsal root ganglion situated along the vertebral column next to the spine. Reactivation of the virus results in shingles.
The immune system is what keeps the virus inactive, so if it’s compromised, shingles can result. The condition is more common in immune-compromised patients (e.g. due to HIV/AIDS, cancer, or high/long-term stress). Shingles can attack children from age two or three on, but the likelihood of suffering an outbreak increases with age. Approximately 10-20 per cent of people who have had chickenpox will get shingles.
THE SIGNS OF SHINGLES
Symptoms come in two stages: the prodromal stage, which is when the rash is about to appear, and the eruptive stage, when the rash appears. Classic symptoms of the prodromal stage include nausea, fever, chills, headaches and a lack of feeling or intense pain on one part of the body or face. The rash generally manifests on one side of the chest and abdomen. Symptoms vary in severity and can last up to 30 days but, in extreme cases, can last for months.
Cunningham has seen many cases of severe shingles and says symptoms can be debilitating: “It generally forms in a very specific pattern that’s based usually on the trunk of the body. If you’ve seen someone with shingles, you will have seen the crusty rash it causes. Pain is the worst of all symptoms; I have seen cases of people screaming with agony requiring a morphine drip – it can be a prolonged, intense and unbearable pain. Patients can get so run down and stressed when the symptoms that come from having shingles won’t let up, that I have seen suicides as a result.”
It’s estimated that 150,000 cases of shingles occur in Australia each year. That’s a rate of 830 cases per 100,000 people. According to the US Centres for Disease Control and Prevention, an estimated 1 million cases occur in the US annually.
IS IT CONTAGIOUS?
You can’t contract shingles from someone else if you have not been exposed to chickenpox and don’t harbour the virus in your system. But because the shingles rash contains active virus particles, someone who has never had chickenpox can get it [chickenpox] from exposure to shingles.
Dr Christopher Beisel, a microbiologist at the National Institute of Allergy and Infectious Diseases in the US, says that “although herpes zoster isn’t strictly highly contagious, immune-deficient people or those who haven’t been exposed to chickenpox should definitely keep away from shingles patients. It can be a very serious virus, especially in the elderly; one really should avoid getting it.”
Shingles can badly affect the liver and the brain, and in extreme cases can prove fatal. Neurological complications can also arise, for example encephalitis and vasculitic stroke. According to the World Health Organization, 8-15 per cent of people suffer permanent neurological damage, impaired vision, or problems of bowel or bladder function as a result of herpes zoster.
Herpes zoster ophthalmicus (HZO), or ocular shingles, can in severe cases cause blindness. Uveitis (inflammation inside the eye) occurs in about 40 per cent of patients with HZO and generally starts one to three weeks after the rash appears. Symptoms include sensitivity to light and impaired vision. Immediate medical attention should be sought if any of these symptoms occur, to avoid glaucoma and other iris irregularities.
Postherpetic neuralgia (PHN) is a chronic pain problem associated with shingles. It’s the prolonged pain that can remain after the shingles have gone. For most, PHN will go away within a year. However, for about 40 per cent of PHN sufferers the pain continues long-term.
When herpes zoster occurs, treatment should begin within 72 hours. Clinicians normally prescribe antiviral medication such as acyclovir or valacyclovir. According to the US National Institute of Neurological Disorders and Stroke, antiviral medications reduce the likelihood of getting prolonged pain by half. These drugs do not kill the virus but work by stopping it from multiplying.
The most recent and advanced antiviral testing is occurring in Wales. FV100 is currently in stage two of testing, in a trial led by Professor Christopher McGuigan, deputy pro vice chancellor at Cardiff University, who has been working on the project for 15 years. “Antivirals currently on the market aren’t very effective,” he says. “FV100 is the first antiviral targeting shingles and chickenpox specifically. By December  we will know if phase two has been successful so we can move onto the final stage. We believe this drug will transform the standard of care for antiviral therapy.”
In 2006, the US Food and Drug Administration approved a VZV vaccine (Zostavax) for use in people 60 years and older who have had chickenpox. When the vaccine becomes more widely available, many older adults will for the first time have a means of preventing shingles.
Researchers from the Shingles Prevention Study found that by giving this age group the vaccine, the expected number of HZ cases were reduced by half in people who got the disease despite immunisation; complications were dramatically reduced; and cases of PHN were reduced by two-thirds in the group of 38,500 people tested.
Results unveiled at the 48th Annual Meeting of the Infectious Diseases Society of America in Vancouver in October went further, revealing adults aged 50-59 using Zostavax had a reduced incidence of shingles by nearly 70 per cent. The company behind the drug is now seeking approval from the FDA for use in this age group.
The vaccine has been approved in Australia, but it is not yet available for use due to a lack of supply. It’s not yet known when it is likely to arrive. Though the results are positive, there are problems with the price point. Researchers from the University of Colorado in Denver recently surveyed almost 600 primary care physicians and found less than half strongly recommended the new vaccine due to cost. The vaccination costs 10 times more than other commonly prescribed adult vaccines in the US.
Cunningham and his team at the Millennium Institute are currently undertaking trials to create a new vaccine against shingles. The Australian General Practice Research Network (GPRN) database reports that between January 2001 and December 2005, 10 per cent of Australian patients with HZ developed PHN. The yearly cost on the healthcare system during this period for PHN has been estimated at $19-$30 million. “PHN is nasty, it can cause severe depression and increase fragility in elderly people; they can end up in nursing homes because it’s so debilitating,” says Cunningham. It’s hoped the new vaccine being worked on in Australia will lessen the pain of PHN.
Cunningham says that the vaccine being tested in Australia works in a different way from the American one: “The vaccine we are testing isn’t a live vaccine meaning, if successful, it can be used in people who have had transplants. Zostavax can’t because it’s a live vaccine. There’s a good chance our vaccine will work and if successful it will be useful to have two vaccines of differing types around the world as they’ll be used in different ways; there will be more availability and it will also bring the cost down. Hopefully, one day we’ll make a vaccine that’s 100 per cent perfect but we haven’t got there yet.”