In recent years the use of the condom has increased rapidly because of its potential to protect against AIDS. It has been particularly effective in combination with nonoxynol-9 (NP-9), which stopped the reproduction of HIV virus in 60 seconds in vitro. Benzalkonium chloride in .0% concentration also killed HIV in vaginal secretions. Epidemiological studies confirmed the efficacy of the condom to stop HIV infection. In an experiment involving 263 prostitutes in Nairobi, Kenya, 80% of them used condoms, and seroconversion diminished in direct relationship with the frequency of use. HIV infection was absent in 14 partners using the condom regularly for 2 years among 31 seropositive hemophiliacs, while 3 women (17%) of 17 couples not using it regularly got infected. In a study of 43 heterosexual couples (13 women and 30 men) where 1 partner was infected, 6 men and 16 women became seropositive after 4 years. Only 35% of the women used the condom. Heterosexual AIDS increased from 1% in 1985 to 6.8% in 1989, and a 60-year-old man became seropositive after repeated episodes of oral sex with a female seropositive prostitute. In Italy, seropositive inmates make up 15-18% of the prison population. The risk of transmission after sex with an infected person is .01%, but the condom can reduce this risk by 90%. A public education campaign in the US has boosted the sale of condoms by 22%. The risk of infection is 1 in 5 billion after a single sexual act with a low risk person; however, the risk of transmission was an extremely high 2 infections/3 cases when the condom was not used in 500 sexual acts with a seropositive person. 100 acts with a single seropositive person using the condom poses a much higher risk of infection than a single unprotected act with 100 partners who have a 1% risk of having the disease. Although the public campaign extolling the virtues of the condom may generate a sense of false security, the available evidence suggests that the condom provides a unique and effective barrier to the transmission of the infection.
