This is the ValueSet that contains all the codes in WHO PreQualificaiton Vaccine Product Ids (http://smart.who.int/pcmt-vaxprequal/ValueSet/PreQualProductIds) and WHO PreQualificaiton Vaccine Product Ids (http://smart.who.int/pcmt-vaxprequal/ValueSet/PreQualProductIds). E.g. what you have to deal with if you get resources containing codes in either of them