Most British children will contract chicken pox during their childhood. The disease is almost a rite of passage – the itching, discomfit and, of course, the distinctive rash. Many people have somewhat nostalgic memories of chamomile-soaked days off school, with their equally spotty siblings and an exhausted parent.
Chicken pox is caused by the varicella zoster virus, one of eight herpes viruses known to infect humans, and is thought to have been infecting humans for millennia. The virus is spread through the air, and can also be spread via contact with the blister on the skin before they heal over. Chicken pox presents as a head-downwards rash, usually very distinctively. In patients aged 1 to 15 years, symptoms, although uncomfortable, are rarely serious.
One in five of those who contract chicken pox as a child will go on to suffer from shingles, known as herpes zoster. This can be made more likely if you are immunocompromised, such as from cases of HIV or cancer, or elderly. Shingles occurs as the varicella zoster virus remains dormant in the body’s nerve tissues where it is repressed by the immune system. Typically a shingles rash will occur in a single painful stripe down one side of the body, following the line of the nerves.
Chicken pox is surprisingly sparsely documented in extreme antiquity. It can be hard to decipher references to diseases in ancient texts, especially when the main symptoms spots – are they describing small pox, herpes, syphilis or just a spot? One approach is to see what the treatments offered were. The more serious the disease, the more extreme the treatment is likely to take, from bloodletting (popular from ancient Greece to the middle ages) to animal dung ointments, noted in the Ebers Papyrus from c 1550 BCE Egypt as having healing properties and working to ward off bad spirits.
Probably the earliest description of chicken pox can be credited an ancient Babylonian text from over 2000 years ago, but the description of a “yoke around the [..] abdomen or pelvis” is more compatible with shingles. The ancient Egyptians suggested treatment of a particular rash with an oatmeal bath, which is still today a popular method of reliving the chicken pox itch.
In the Devi Mahatmya, a Hindu religious text from c 400 CE chicken pox patients should be treated by placing a jar of water at the head of the bed, spreading neem leaves around the doorways of the house and over the bed and all the lamps in the house should be extinguished. Lamp smoke would irritate the rash, causing itching and possible bacterial infection. Neem leaves prevent mosquitoes and the bundles at the doorway would act as a warning to guest that there was disease in the house. The water by the bedside prevents the infected from wandering off to look for a drink. All in all, a very effective treatment and quarantine procedure.
The ancient Greeks identified shingles and called it zoster after word for girdle, as the most common place for the rash to appear is in the peripheral nerves of the back that wrap around the abdomen. Similarly the Romans referred to the disease as cingulus (belt) which is where we get the word “shingles” from.
The source English name “chicken pox” for the childhood rash is more disputed. There are theories that the name arose because the blisters made the skin look like it had been pecked by a chicken or, as proposed by Doctor Samuel Johnson in the 18th century, that is was the coward’s form of Small pox. More likely the name arises from the old English word “giccan” to itch or itchy pox.
In the 1767, the English physician William Heberden demonstrated that chicken pox was not a lesser form of small pox and that a patient who has had chicken pox would remain immune to the disease. It took over a hundred years for another scientist, Rudolf Steiner in 1875, to identify that chicken pox was caused by an infectious agent. He did so by extracting fluid from the blisters of an infected person and rubbing it on the skin of healthy volunteers, they too devolved am itchy, blistering rash.
When Dr. James von Bokay proposed that chicken pox and shingles were, in fact, caused by the same virus he tested the hypothesis by rubbing fluid extracted from shingles blisters into the skin of healthy children. When they contracted chicken pox, it appeared to confirm his suspicions, although it wasn’t until 1953 that Thomas Huckle Weller isolated virus from both illnesses and confirmed that they were, in fact, the same.
Michiaki Takahashi, a Japanese virologist, developed a live attenuated varicella zoster virus vaccine in 1972 and Japan became one of the first countries to routinely vaccinate against chicken pox. The USA followed soon after and cases of chicken pox dropped from approximately 4 million per year to less than 400, 000 in 2005. The vaccine has been adopted into childhood routine immunisations in Canada and Australia and is gaining wider acceptance across Europe.
The UK has targeted recommendations for the vaccine, such as health care workers, and those with regular contact with immunocompromised persons. By 2005 all NHS works had had their immunity determined and been immunised if they were non-immune.
Whilst chicken pox is rarely fatal, in a pregnant woman the complications can be severe. Risks to the fetus include encephalitis, damage to the development of the eyes, and hypoplasia of the extremities amongst other complications. Newborns who develop symptoms are at a high risk of developing pneumonia and other serious complications of the disease. Meanwhile in the USA vaccine coverage for chicken pox is currently at almost 95% in adolescents aged 13 to 17 years. Over the last year, three and a half million cases of varicella, 9,000 hospitalisations, and 100 deaths are prevented by varicella vaccination in the United States, according to the CDC.
So why does the NHS not currently offer the vaccine to the whole population? There is a worry that, by reducing the numbers of the less harmful childhood chicken pox, there would be a loss of herd immunity for adults. Adults who suffer from chicken pox are much more likely to suffer complications such as pneumonia and the natural boosting of immunity by expose to the virus by expose to infected children is thought to keep cases of adult chicken pox and shingles down.
In the US, overall rates of herpes zoster (shingles) appears to be increasing, but whether or not this is linked to the increased rate of varicella vaccination is yet to be determined. Many factors can play in to whether or not someone develops shingles, from smoking to obesity to age.
Chicken pox vaccines are still provided on the NHS where there is a clinical need, for example if a child has a sibling or parent with a weakened immune system. Many parents in the UK will make sure their child contracts chicken pox as a child, but if you are worried you do not have immunity, your GP can carry out a blood test to check.
Treatment for chicken pox hasn’t progressed much since the days of neem leaves and oatmeal baths. As long as the young patients can be prevented from scratching the blisters, there will likely be no permeant scarring, the fever will pass and the rash will last only a few days. However some argue that there is no need for this disease at all in modern times and it should go the way of small pox. If we are capable of preventing a disease, should we take those steps to eradicate it?
Adding chicken pox to the MMR vaccine (marketed as the MMRV vaccine) has been proposed in the UK since 2007. However uptake of MMR is far from universal and some parents are still unwilling to vaccinate their children against the more frequently deadly measles, an outbreak of which hospitalized 88 and killed one in Swansea during 2013. No child needs to suffer from a vaccine-preventable disease, from diphtheria to meningococcemia. However chicken pox will remain a childhood “tradition” for a few more generations to come.