Is A Single Dose Enough? All You Need to Know About Varicella Vaccine

Thanks to advances in technology, we now have more vaccines available to prevent various diseases. But it's important to understand the relevant information before getting vaccinated. So, this blog will provide you with all the information you need to know before getting the varicella vaccine. Let’s get started!

Varicella is an acute infectious disease caused by the varicella-zoster virus, which commonly affects children aged under 12. Although almost all individuals develop lifelong immunity after varicella infection, the virus may remain latent in the body and recur many years later as herpes zoster (shingles).

Varicella patients often develop the following symptoms:

Fever and itchy, red rashes.

Red rashes that develop gradually within 5 days, spreading from the torso to the face and limbs.

The rashes first appear as flat spots and later as vesicles. The vesicles continue for 3 - 4 days, then dry up and form scabs.

The patient usually recovers in about 2 - 4 weeks.

Persons who have received varicella vaccination may still be infected, but the duration of illness is usually shorter than that of non-vaccinated persons.

Varicella is mainly transmitted through air droplets when an infected person coughs, sneezes or speaks, or via direct or indirect contact with the discharges from vesicles and mucous membranes of infected persons. The incubation period is usually 14-16 days, and the rashes are extremely contagious in the early stage.

Some patients may develop bacterial infections in their wounds. People with weakened immunity or pregnant women may suffer from severe complications such as pneumonia, encephalitis and bleeding disorders, and even death. So, getting a varicella vaccine is the best way to prevent infection and lower the chances of complications, hence reducing the economic burden on families and society.

How can I prevent varicella?

Maintain good personal hygiene

Keep your hands clean by washing them with liquid soap for at least 20 seconds. If you experience symptoms, wear a mask, avoid going to crowded places, and seek medical attention as soon as possible.

Maintain good environmental hygiene

Regularly disinfect frequently touched surfaces such as furniture, toys, and shared objects, and maintain good indoor ventilation.

Vaccination

Varicella vaccine is a live virus vaccine. It works by exposing the body's immune system to a certain dose of the virus to help develop immunity. This helps the body to produce an immune response rapidly when exposed to the virus in the future, thus avoiding infection. About 90% of people who get vaccinated can develop immunity to the virus.

Is a single dose enough to develop immunity?

Both children and adults can get vaccinated against varicella. It's recommended that children receive their first dose at one year old, followed by a second dose three months later. They can also receive the second dose at the age of 5 to enhance immunity to varicella. Adults who have not been vaccinated against varicella or have no infection record can receive a vaccination to strengthen their immunity.

Under the Hong Kong Childhood Immunisation Programme, children receive two doses of the varicella vaccine (please refer to the programme for details). This is a safe and effective way to prevent the disease. Before getting vaccinated, parents can consult their family doctor or the Maternal and Child Health Centre of the Department of Health for more information. By getting vaccinated against varicella, individuals can reduce the burden on themselves and their families, as well as contribute to maintaining public health in the community.

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