A total of infants developed clinical or radiological signs of TB but survived the infection, while 72 died from TB.
While some blamed the accident on BCG itself by postulating reversion to full virulence, such a possibility was conclusively disproven. Rather, by combining clinical, microbiological, and epidemiological data, the chief public health investigator Dr.
Moegling concluded that the BCG vaccine had been contaminated with variable amounts of fully virulent M. Here, we summarize the conclusions drawn by Moegling and point out three lessons that can be learned.
This shows the high constitutional resistance of humans to the bacillus. Second, four semiquantitative levels of contamination were deduced by Moegling from the available data. While at low levels of M. This shows the dominating role of dose for innate resistance to TB. Third, two infants inoculated with the lowest dose nevertheless died of TB, and their median time from inoculation to death was substantially shorter than for those who died after inoculation with higher doses.
This suggests that infants who developed disease after low dose inoculation are those who are most susceptible to the disease. We discuss some implications of these lessons for current study of genetic susceptibility to TB.
