Varicella vaccine
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.
Typhoid vaccine
Typhoid vaccines are vaccines that prevent typhoid fever. Several types are widely available: typhoid conjugate vaccine (TCV), Ty21a (a live vaccine given by mouth) and Vi capsular polysaccharide vaccine (ViPS) (an injectable subunit vaccine). They are about 30 to 70% effective for the first two years depending on the specific vaccine in question. The Vi-rEPA vaccine has been shown to be efficacious in children.
The World Health Organization (WHO) recommends vaccinating all children in areas where the disease is common. Otherwise they recommend vaccinating those at high risk. Vaccination campaigns can also be used to control outbreaks of disease. Depending on the vaccine, additional doses are recommended every 3 to 7 years. In the United States the vaccine is only recommended in those at high risk such as travellers to areas of the world where the disease is common.
The current vaccines are very safe. Minor side effects may occur at the site of injection. The injectable vaccine is safe in people with HIV/AIDS and the oral vaccine can be used as long as symptoms are not present. While it has not been studied during pregnancy, the non-live vaccines are believed to be safe while the live vaccine is not recommended.
The first typhoid vaccines were developed in 1896 by Almroth Edward Wright, Richard Pfeiffer, and Wilhelm Kolle. Due to side-effects newer formulations are currently recommended. Typhoid vaccines are on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. The wholesale cost in the developing world is about US$4.44 per dose as of 2014. In the United States they cost $25–50.