What is varicella (chickenpox)? How did it originate?
Varicella, commonly known as chickenpox, is an infection caused by the varicella zoster virus. It is highly contagious, spreading in a similar way to flu, and causes a blister-like rash on the skin. It is not life-threatening but can cause complications.
What are the symptoms of chickenpox?
After between 1 and 3 weeks of being exposed to the chickenpox virus, red spots start to appear on the skin. The spots fill with fluid, and may burst, and then scab over and become itchy. In the meantime, spots may spread to other parts of the body.
Other symptoms include fever, muscles aches and pains, and a loss of appetite. Symptoms are usually worse for adults than children.
You are infectious from 2 days before spots appear until they have crusted over, which is usually 5 days after they appear.
How is chickenpox transmitted?
Chickenpox is highly contagious and you can catch it just by being in the same room as someone infected with it. You can also catch it from the fluid in the blisters, for example by touching bedding or clothing.
What is the transmission seasonality?
If you are travelling, note that chickenpox is a seasonal disease, and most cases occur in winter and spring. Although Singapore does not have seasons, you may wish to take precautions and take the vaccine if you are travelling to countries where it is winter or spring. There is often a peak between March and May, although this has been less noticeable in recent years.
What are the infected areas in the world?
The chickenpox virus is common in most countries around the world and often crops up in schools and nurseries in Singapore, where many children are clustered together and are in close contact with one another.
What is a chickenpox certificate?
A chickenpox vaccination certificate proves you have been vaccinated against the disease.
Is chickenpox curable?
For healthy children in whom the chicken pox infection manifests in only a mild form, treatment is directed at reducing the itch and discomfort. Children with chickenpox should not receive aspirin because of the possibility of causing a complication called Reye’s syndrome, which is a very serious illness that can cause liver and brain damage.
There are also antiviral medications that can be used to treat chickenpox. These are usually most effective when taken within the first 24 hours of developing the illness. They reduce the severity and duration of the disease, as well as reduce the likelihood of complications but most children do not need them.
Most adults would benefit from them if taken early enough, especially those who have impaired immunity as they are more susceptible to severe chickenpox.
How can you prevent chickenpox?
The best way to prevent chickenpox is to get the chickenpox vaccine.
The chickenpox vaccine is very safe and effective at preventing the disease.
MOH, under the National Adult Immunisation Schedule, has included the varicella or chickenpox vaccine as one of the recommended vaccines for adults – that is, if they have not already gotten the vaccine and especially if they have not yet contracted the disease.
Two doses are recommended, the second given 4-8 weeks after the first.
Most people who get the vaccine will not get chickenpox. If a vaccinated person does get chickenpox, it is usually mild—with fewer red spots or blisters and mild or no fever.
The chickenpox vaccine prevents almost all cases of severe disease.
How long before a trip do you have to get the chickenpox vaccine?
You should allow at least 4 weeks to ensure you complete the full schedule of 2 doses.
Who should get the chickenpox vaccine?
The chickenpox vaccine is recommended for the following groups of people:
- Healthcare professionals
- People who care for or are around others with weakened immune systems
- Child care workers
- Residents and staff in nursing homes and residential settings
- College students
- Inmates and staff of correctional institutions
- Military personnel
- Non-pregnant women of child-bearing age
- Adolescents and adults living with children
- International travelers
Although it is not compulsory in Singapore to vaccinate children against chickenpox, MOH recommends that children have the vaccination between 12 to 18 months.
The Ministry of Health’s Expert Committee on Immunisation has recommended that children below 13 years of age should receive two doses with a recommended interval of at least three months. The first dose should be given at 12 months of age and the second dose at least three months later, by 18 months of age. Those who are 13 years and above continue to receive two doses, at six-week intervals.
Who should not get the chickenpox vaccine?
The CDC does not recommend the chickenpox vaccine for people who have had severe allergies to previous doses of the vaccine or are allergic to any component of the vaccine. Those who are clinically immunosuppressed, either due to drug treatment or illness, are also not advised to get the vaccine.
This includes babies whose mothers have had immunosuppressive treatment while they were pregnant or breastfeeding.
The vaccine is also not recommended for pregnant women. If you are travelling to a high-risk region or think that you may be in danger of contracting chickenpox, speak to your health provider. If you are mildly ill, you may also wish to discuss with your health provider about whether you can receive the vaccine.
Those who are moderately or severely ill should wait till they recover to get the vaccine.
What is the minimum age requirement for the chickenpox vaccine?
The minimum age to get the chickenpox vaccine is 12 months.
What is the effectiveness of the chickenpox vaccine?
Two doses of the vaccine give about 98% protection in children and about 75% protection in teenagers and adults.
What are the side effects of the chickenpox vaccine?
As a guide, common side effects include redness, swelling and pain at the injection site, and a fever. Up to one in 10 people experience a rash similar to chickenpox, mild cold-like symptoms, irritability and itching at the injection site.
1 in 100 people experience more severe side effects, including:
- swollen glands, sore throat, headache, runny nose or cough
- Nausea and vomiting
- a blistering rash
- muscle or joint pain
- very high fever
- sleepiness, tiredness, or feeling unwell in general.
How many jabs are needed?
Two doses are given, at least 4 weeks apart. The exact spacing between doses depends on the brand of vaccine given and the age of the person receiving the vaccine.
When and where was the last outbreak of chickenpox?
Chickenpox is common and mostly affects children, although you can get it at any age.