Varicella-Zoster Virus (VZV)
The Varicella-Zoster Virus (VZV) causes two distinct diseases, varicella (chickenpox), usually during childhood, and herpes zoster, HZ (shingles), usually much later in adult life.
The first infection with the varicella-zoster virus causes chickenpox. After recovery, the virus remains latent (sleeping) in spinal nerves and may reactivate years later, causing shingles.
What is chicken pox?
Chicken poxis contagious viral infections that over 90% of people get during childhood unless they have been immunised.The virus after the infection may stay in the nerve cell of the body and may activate again in later life (typically in adults over 50 years of age) causing shingles.The infection, lasting about 7- 10 days usually presents with a fever. Then rashes will appear on the chest and trunk of the body and sometimes spread to the extremities. It starts of as red, itchy lumps, which then become blisters.
How is chicken pox spread?
The infection is spread through droplets from an infected person’s cough or sneezes. It can also be spread through touching of the fluid from the ruptured blisters.
Chicken pox can also be caught (although rare) from the fluid of someone with shingles.
Chicken pox is very contagious from the beginning of the illness (2 days before rash appear) until about 5 days after the first spot appear).
How long does it take to develop?
The incubation period is approximately 14 to 15 days.
Should parents keep their children away from school or childcare?
Yes, the infected child should be kept at home for 5 days after the first rash appears, or until or blisters are dry.
What is the treatment for chicken pox?
There is no specific treatment available for chicken pox. Symptomatic treatment such as paracetamol or calamine lotion can be given to ease the fever or the itch cause by the rash. For immune compromised patients, doctor may prescribe an anti viral medication to reduce the severity of the disease.
What is shingles?
The primary infection (chicken pox) may cause some virus to stay in the nerve cell. When these virusesare reactivated later in life, this is called shingles. Shingles is not a new infection. It is a new outbreak of the old infection. Therefore, shingles only happens in people who already had chicken pox.
Shingles starts with pain in the affected nerve area where the virus had been dormant. The pain can range from a tingling sensation to very severe burning pain, indicating nerve damage.
Within 5 days from the start of the pain, a rash will appear that is localised to the affected area where the nerve is. This can be a band of skin around the chest, abdomen, face or less commonly an arm or a leg.
How is shingles spread?
A person is not able to catch shingles from someone else with shingles or with chicken pox, however because shingles blisters do contain active viruses, this may be a mode of transmission to an unvaccinated person who has not contracted chicken pox before.
What are the complications of shingles?
The pain caused by shingles can persist for many weeks or months. In addition, secondary infection of the rash can happen and may be quite severe, causing scarring.
What is the treatment for shingles?
Since shingles usually affect the elderly (who may be immune compromised), anti viral medication can be given to reduce the severity of the illness. Other symptomatic treatments include paracetamol and pain killers.
Chicken Pox vs. Shingles
Table 1: Comparison of Chicken Pox and Shingles
|Cause||Caused by primary infection with VZV||Secondary infection from reactivation of latent VZV|
|Age when affected||>90% infection occurs before adolescence||Only occurs in adults with prior VZV infection|
|Population affected||Children, but may be extended to adult||Usually adults aged 50 years or older|
|Signs & Symptoms||Starts with mild fever
Loss of appetite
Itchy rash that becomes blisters
|Starts with altered sensation (eg: tingling, burning, numbness at rash area)
Unilateral, localized rash that becomes blisters
|Area of rash||
Rash is usually widespread over trunk and face with some on arms and legs
Image Source: Wikipedia
Rash is localized, in infected nerve supplies, typically on the back/chest/face
Image Source: Everyday Health
|Mode of transmission||Contact with infected droplets of saliva in the air initially, then contact with liquid from rash blisters may cause chickenpox||Contact with liquid from rash blisters that may cause chickenpox|
|Contagiousness||Infectious from 1-2 days before rash appears until after the rash blisters have dried up||Infectious once the rash becomes blisters until after the rash blisters have dried up|
Different vaccines are used for prevention of chicken pox and shingles in Malaysia. Table 2 shows the different types of vaccine and their appropriate use.
In general, all Varicella vaccines are indicated from infants aged 12 months (9 months for PriorixTetra) and above. The only Shingles vaccine (Zostavax) is indicated for individuals aged 50 years and above in high-risk populations. All the vaccines are administered as a subcutaneous (SC) injection and would probably require only a single dose. However, a subsequent dose may be given depending on national immunization requirements.
With these vaccines, the most common adverse events are fever, pain and swelling at injection site and occurrence of Varicella like rash.
All of the vaccines should be stored appropriately in accordance to their respective storage and handling recommendations.
Any vaccinees requiring more information should contact their local general practitioner or the nearest available pharmacists.
Table 2: Types of vaccine available in Malaysia
|Last Reviewed||:||25 February 2017|
|Writer||:||Jenny Thong Chen Ni|
|Accreditor||:||Dr. Yvonne Khoo Siew Khoon|