You can use "+" for concatenation although it is not recommended as this is a WordBasic operator. You should use "&".
When using the string concatenation character "&" be sure to insert a space before and after this operator.
String Concatenation (&)
This operator can be used to join two or more strings together.
This operator can also automatically convert between types as it combines a resultant string.
It can be used to combine several different variable types into a string without any explicit conversion.
String Concatenation (+)
This can also be used as a string addition operator to join two or more strings together.
If you try to use this operator with multiple variables types you will receive a "Type Mismatch" error.
Dim MyNumber As Variant
MyNumber = "2"
MyNumber = MyNumber + MyNumber + MyNumber
Msgbox MyNumber ' "222"