Varicella vaccine in the UK. 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
WHO disease staging system for HIV infection and disease WHO disease staging system for HIV infection and disease WHO Disease Staging System for HIV Infection and Disease was first produced in 1990 by the World Health Organization and updated in September 2005. It is an approach for use in resource limited settings and is widely used in Africa and Asia and has been a useful research tool in studies of progression to symptomatic HIV disease. Most of these conditions are opportunistic infections that can be easily treated in healthy people. The staging system is different for adults and adolescents and children. Stage I: HIV disease is asymptomatic and not