Varicella vaccine given subcutaneously (under the skin). It is recommended for all children under 13 and for everyone 13 or older who has never had chickenpox. In the United States two doses are recommended. In the first case a first dose is administered at 12 to 15 months and a second dose at age 4–6 years. For people older than 13 the two doses are administered 4 to 8 weeks apart. The varicella vaccine did not become widely available in the United States until 1995. In the UK, the vaccine is only recommended in people who are particularly vulnerable to chickenpox. The
Technical diving magazine was using the term "technical diving", as an analogy with the established term "technical (rock) climbing". In the US the Occupational Safety and Health Administration categorises diving which is not occupational as "recreational diving" for purposes of exemption from regulation. This is also the case in some other countries, including South Africa. There is some professional disagreement as to what exactly technical diving encompasses. Nitrox diving and rebreather diving were originally considered technical, but this is no longer universally the case as several certification agencies now offer Recreational Nitrox and recreational rebreather training and certification. Some training agencies classify