Varicella vaccine from Japan
|
|
Vaccine description | |
---|---|
Target disease | Varicella (chickenpox) |
Type | Attenuated virus |
Clinical data | |
Trade names | Varivax, Varilrix, other |
AHFS/Drugs.com | Monograph |
MedlinePlus | a607029 |
License data |
|
Pregnancy category |
|
Routes of administration |
Injection |
ATC code | |
Legal status | |
Legal status |
|
Identifiers | |
ChemSpider |
|
(what is this?) |
Varicella vaccine, also known as chickenpox vaccine, is a vaccine that protects against chickenpox. One dose of vaccine prevents 95% of moderate disease and 100% of severe disease. Two doses of vaccine are more effective than one. If given to those who are not immune within five days of exposure to chickenpox it prevents most cases of disease. Vaccinating a large portion of the population also protects those who are not vaccinated. It is given by injection just under the skin.
The World Health Organization (WHO) recommends routine vaccination only if a country can keep more than 80% of people vaccinated. If only 20% to 80% of people are vaccinated it is possible that more people will get the disease at an older age and outcomes overall may worsen. Either one or two doses of the vaccine is recommended. In the United States two doses are recommended starting at twelve to fifteen months of age. As of 2012 most European countries either recommend it for all children or just those at high risk, but not all countries provide the vaccine due to its cost.
Minor side effects may include pain at the site of injection, fever, and rash. Severe side effects are rare and occur mostly in those with poor immune function. Its use in people with HIV/AIDS should be done with care. It is not recommended during pregnancy; however, the few times it has been given during pregnancy no problems resulted. The vaccine is available either by itself or along with the MMR vaccine, in a version known as the MMRV vaccine. It is made from weakened virus.
The chickenpox vaccine first became commercially available in 1984. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. In the United States it costs between 100 and 200 USD.
Varicella vaccine is 70% to 90% effective for preventing varicella and more than 95% effective for preventing severe varicella. Follow-up evaluations have taken place in the United States of children immunized that revealed protection for at least 11 years. Also, studies were conducted in Japan which indicated protection for at least 20 years.