If a person is HIV positive, why are they not allowed to serve a normal full-time mission?
According to the National Institute of Health individuals who are diagnosed as HIV positive need to work closely with their health providers regarding when to start treatment and which medications to take.
Needing this level of health care could interfere with missionary service. Being HIV positive is not the only ailment that could preclude one from missionary service. The church has said:
“Unfortunately, some health problems can present insurmountable obstacles to serving full-time proselytizing missions. The First Presidency has stated: “There are worthy individuals who desire to serve but do not qualify for the physical, mental, or emotional challenges of a mission. We ask stake presidents and bishops to express love and appreciation to these individuals and to honorably excuse them from full-time missionary labors.” In such cases, service missions can be a great blessing, allowing individuals to live at home and receive appropriate medical care while growing and maturing in the service of the Lord. Parents, bishops, and stake presidents can help in encouraging and arranging appropriate opportunities.
Opportunities for service missions can also be found at the Church Web site www.lds.org. Select “Other Resources,” then “Mission and Service Opportunities.” Continuing higher education or technical training to allow better coping with chronic impairment is also an admirable alternative.”