Are missionaries at risk for AIDS? Evaluation for HIV antibodies in 3,207 protestant missionaries.

Serum specimens (n = 6,045) obtained from 3,207 Protestant missionaries serving in 57 countries, including 28 African nations, between 1967 and 1984 were assayed for antibodies to the human immunodeficiency virus (HIV) by enzyme-linked immunosorbent assay (ELISA) screening and Western blot confirmatory testing. Seventy sera (1.2%) from 51 missionaries (1.6%) were ELISA positive; however, on Western blot confirmatory testing none was diagnostic of HIV infection. Twenty-two (43%) of the Western blot tests were read as indeterminate, with band p17 occurring with the greatest frequency (57%), followed by p24 (23%), either alone or in combination. The significance of these equivocal results is unclear, but they do not appear to be a consequence of exposure to either HIV or the related retrovirus HTLV-I. Based on this seroprevalence survey, we conclude that missionary staff and their families were not at high risk of HIV infection between 1967 and 1984, even when serving in regions of high HIV endemicity.