CDC NATIONAL AIDS HOTLINE TRAINING BULLETIN #35 - March 9, 1993
Centers for Disease Control and Prevention

"I have heard that there is some doubt about CDC's conclusions concerning the transmission of HIV by a dentist in Florida. Is there anything to this?"

CDC stands by its conclusion that a Florida dentist with AIDS transmitted HIV to five of his patients during the course of their dental care. Precisely how the transmission occurred remains undocumented.

R.W. DeBry et al., in their February 25, 1993 letter to Nature entitled "Dental HIV Transmission?" suggest that the results of the CDC's investigation of HIV transmission in a Florida dental practice should be considered inconclusive. They base their opinion on their finding that in one type of laboratory analysis, the HIV genetic sequence of one local "control" patient "clustered" with the HIV genetic sequences from the infected dental patients.

It is not surprising that a control patient could be found whose HIV sequence has some similarity to the sequences found in the infected dental patients. However, in reaching their conclusion, the authors ignore the totality of the results of the CDC investigation. What is important is that the HIV sequences of the five infected dental patients are much more like the sequence of the dentist's virus than the sequences of 30 control viruses. The odds that this would happen by chance alone are less than 1 in 100,000. Further, the authors ignore the epidemiologic investigation showing that none of the five dental patients had other risk factors for HIV infection.

Unfortunately, the authors of the letter provide no HIV sequence data which would allow others to independently assess either the validity of these sequences or the correctness of their analyses.

In summary, the epidemiologic, laboratory, and statistical analyses of this cluster support the conclusion that HIV was transmitted from the dentist to the five patients.