Shingles can be a very serious and painful disease, which is why a new vaccination programme is being introduced in the UK.
What is shingles?
Shingles is caused by the same virus as chickenpox, herpes varicella zoster.
The virus can remain inactive in the nervous system for decades, with the body's immune system keeping it in check, but later in life it can flare up again and emerge this time as shingles.
The disease affects the nerves and the skin, causing a painful rash.
Can I catch it from other people?
No. It is not possible to catch shingles itself from someone with the condition. If you have not had chickenpox before, however, you can catch that from someone with shingles.
Infection is usually passed on by direct contact with fluid from the lesions. It is not spread by respiratory droplets.
People with a shingles rash on the body should be advised to keep the affected area covered and to avoid sharing towels, going swimming or playing contact sports. Adults can return to work as soon as they feel well enough, provided that the rash can be covered or the blisters have dried up.
How dangerous is it?
Most of the time, shingles will get better on its own. The painful rash usually lasts around a week and takes two to four weeks to fully heal. In severe cases, however, it can cause serious complications, including hearing loss or brain swelling. Some people may also experience long-term nerve damage, which can cause pain and weakness or paralysis.
Can drugs treat it?
Shingles is caused by a virus so antibiotics will not work. Doctors may prescribe an antiviral drug such as acyclovir to lessen the symptoms. Painkillers are also helpful.
Why vaccinate at the age of 70?
The risk of shingles increases with age, and is most common in people over 50. Indeed, half of people who reach 85 will get it.
It is unclear what triggers a reactivation of infection, but people with low immunity - those who are poorly nourished, have another illness or are taking certain medications - are at increased risk.
It is estimated that 3 in every 1,000 people get shingles in the UK every year.
Shingles is also more likely to cause complications in older people, which is why experts say people in their 70s should be targeted by an immunisation programme regardless of whether they have had shingles or chickenpox before.
Is the vaccine new?
No. The vaccine has been around for some time but has not been widely offered to people in the UK. Some people have paid to have the jab on a private prescription at a cost of around £150.
It is not clear how much the NHS will have to pay per jab but it is likely to be less than this under contracts with pharmaceutical manufacturers.
Is it safe?
The independent advisory expert group, the Joint Committee on Vaccination and Immunisation (JCVI), has reviewed the efficacy and safety data on the shingles vaccine and has recommended that a national immunisation programme be started.
The vaccine contains a live weakened version of the chickenpox virus that stimulates an immune response to boost the body's resilience.
Some people who receive the vaccine may get a chickenpox-like rash near the injection site. As a precaution, this should be covered until it disappears.
The vaccine has been widely used in the US and there have been no documented cases of people getting chickenpox from someone who has received the shingles vaccine.
Is it 100% effective?
The vaccine is thought to work in around half of those who receive it.
A study in 38,000 people showed that vaccination reduced the occurrence of shingles by 50%. Studies also suggest that among the vaccinated who do still develop the disease, the symptoms are less severe.
Research suggests that the shingles vaccine is effective for at least six years, but may last longer.
Can the vaccine be used in children to prevent chickenpox?
Chickenpox is caused by the same virus that the shingles vaccine protects against.
The UK does not recommend routine vaccination of children against chickenpox. It is sometimes offered to people who are at greater risk of serious infection.
Some say that vaccinating children against chickenpox could cause an increase in the incidence of shingles in the elderly.
The theory is that once people have had chickenpox, every time they come into contact with an infected youngster their body's defence system receives the equivalent of a booster jab, building up resistance against the disease throughout adulthood.
If children no longer harboured the disease, a rise in shingles among adults could, in principle, follow.