Rules for chemical formulas (Back to search) 1  Enter a sequence of element symbols followed by numbers to specify the amounts of desired elements (e.g., C6H6). 2  Use correct case for element symbols. 3  Elements may be in any order.  If only one of a given atom is desired, you may omit the number after the element symbol.
Half of all varicella zoster cases occur in children between the ages of 5 and 9. It has been estimated that, before the chickenpox vaccine was introduced in the U.S. in 1995, only 10 percent of Americans over the age of 15 had never had chickenpox.
The vaccine is available both by itself and in combination with other vaccines. This includes with the rubella vaccine and mumps vaccine to make the MMR vaccine, first made available in 1971. The addition of the varicella vaccine against chickenpox to these three in 2005 gave the MMRV vaccine. The vaccine works equally well in all formulations.