Chickenpox Vaccines - Dosages and Precautions
Created by Parentune Support Updated on Jul 17, 2012
What is Chickenpox ?
Varicella (Chickenpox) was, until recently, one of the most common of childhood diseases. Before there was a vaccine, almost everyone got it. Chickenpox is caused by the varicella zoster virus (VZV). VZV is a DNA virus and is a member of the herpes virus group. VZV persists in sensory nerve ganglia. Primary infection with VZV results in chickenpox. Herpes zoster (shingles) is the result of recurrent infection. The virus is believed to have a short survival time in the environment.
Symptoms of Chickenpox
Its most recognizable feature is an itchy rash all over the body. It also causes fever and drowsiness. It is spread from person to person through the air, by coughing, sneezing or breathing, and can also be spread by contact with fluid from the blisters.
It usually takes 2–3 weeks from the time of exposure for a person to become ill, and an infected person is contagious from 1 or 2 days before the rash appears until all the blisters are dried up, usually 4 to 5 days after. Also Read this: Nipah Virus (NiV) Signs & Symptoms, Precautions
Chickenpox is usually mild, but it occasionally causes serious problems. The blisters can become infected, and some children get encephalitis. Among infants less than 1 year old who get the disease, about 1 in 250,000 die. For older children, about 1 in 100,000 die. If a woman gets chickenpox just before or after giving birth, her baby can get very sick, and about 1 in 3 of these babies will die if not treated quickly. About 1 child in 500 who gets chickenpox is hospitalized (about 1 in 50 adults). After a person has chickenpox the virus stays in the body. Years later it can cause a painful disease called herpes zoster, or shingles.
DOSAGE AND ADMINISTRATION
Children between 15 months and 12 years of age
Only one dose of 0.5 ml is given subcutaneously.
Adults and Adolescents from 13 years of age
Two doses, each of 0.5 ml, are given subcutaneously to complete the course with an interval of approximately 8 weeks (minimum 6 weeks) between the first and second doses. There is no information on the use of Chickenpox vaccine in the elderly. Although Chickenpox vaccine is not intended for routine use in children, it may be given to children between 15months and 12 years of age to prevent them getting chickenpox and passing the infection on to people in whom chickenpox can be a very serious disease. After one dose of single-antigen varicella vaccine, 97% of children 15 months to 12 years of age develop detectable antibody titers. More than 90% of vaccine responders maintain antibody for at least 6 years. Among healthy adolescents and adults 13 years of age and older, an average of 78% develop antibody after one dose, and 99% develop antibody after a second dose given 4 to 8 Weeks later.
Immunity appears to be long lasting, and is probably permanent in the majority of vaccines. Breakthrough infection is significantly milder, with fewer lesions (generally fewer than 50), many of which are maculopapular rather than vesicular. Most persons with breakthrough infection do not have fever.
Chickenpox vaccine must be injected under the skin usually in the upper arm. Your nurse or doctor may wipe the skin with alcohol or other disinfecting agents and will let the skin dry before the injection.
Your doctor or nurse will take care that Chickenpox vaccine is not injected into skin or the bloodstream.
If the appointment for the second injection is missed, the second dose should still be given as soon as this can be arranged after the due date. The second injection will ensure that protection against chickenpox will be continued.
If exposure to varicella does not cause infection, post exposure vaccination should induce protection against subsequent exposure. If the exposure results in infection, there is no evidence that administration of varicella vaccine during the incubation period or prodromal stage of illness increases the risk for vaccine-associated adverse reactions. Although post exposure use of varicella vaccine has potential applications in hospital settings, pre exposure vaccination of all healthcare workers without evidence of varicella immunity is the recommended and preferred method for preventing varicella in healthcare settings.
Varicella outbreaks in some settings (e.g., child care facilities and schools) can persist up to 6 months. Varicella vaccine has been used successfully to control these outbreaks.
CONTRAINDICATIONS AND PRECAUTIONS
Chickenpox vaccine is not suitable for everyone.Chickenpox vaccine must not be given if the answer is "Yes" to any of the following:
- Has the person who is to receive Chickenpox vaccine:
- Had an allergic reaction to Chickenpox vaccine following the first dose?
- Had an allergic reaction to any other chickenpox vaccine, or to neomycin, or to any of the ingredients listed above?
- Any illness that weakens the immune system (such as blood disorders, or infections)?
- Recently received or still taking any treatment that can weaken the immune system?
Also, is the person who is to receive Chickenpox vaccine:
- Pregnant or even possibly pregnant?
- Under 13 years of age? Chickenpox vaccine will not usually be given to children who are less than 13 years old. It may be given to children between the ages of 1 and 12 years of age to prevent them getting chickenpox and passing the infection on to people in whom chickenpox infections can be a very serious disease.
- Chickenpox vaccine will, or may be, delayed if the answer to the following is "Yes":
- Does the person who is to receive Chickenpox vaccine have a high temperature or an infection?
- Has the person who is to receive Chickenpox vaccine had a blood or plasma transfusion, or human immunoglobulin within the last 3 months? If so, the antibody response to Chickenpox vaccine may be low so it is usual to wait for 3 months before giving Chickenpox vaccine.
- Is the person who is to receive Chickenpox vaccine due to undergo treatment that might weaken their immune system?
Take Special care with Chickenpox Vaccine
If the answer is "Yes" to any of the following questions, talk to your doctor or nurse before the vaccine is given.
Does the person who is to receive Chickenpox vaccine:
- Come into regular contact with pregnant women?
- Come into regular contact with people for whom the chickenpox virus could cause serious health risks, such as people who have a weak immune system or people receiving any treatment that can weaken the immune system?
The disclaimer note:
"This blog is for information sharing only & in no way of a prescriptive nature. Parents should consult the Doctor before opting out for any vaccination for their child at all times."