MMRV vaccine mumps, rubella (German measles), and varicella (chickenpox) because the risks of these diseases far outweigh the risks of vaccinating against them. In particular, the World Health Organization recommends varicella vaccination in countries where the vaccine is affordable, the disease is a relatively important problem, and high and sustained vaccine coverage can be achieved. The U.S. and a few other countries have widely implemented this. MMR and varicella vaccine are given at roughly the same time and a booster injection is recommended for both. The MMRV vaccine, a combined MMR and varicella vaccine, simplifies administration of the vaccines. Doctors are advised
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