Probability of introducing diseases because of false negative test results.

The use of diagnostic tests for the selection of healthy individual persons or animals for inclusion in certain groups carries with it an inherent risk of including those with infections because they falsely reacted negatively. The factors of sensitivity of the test, prevalence of the disease, and the size of the group all influence the degree of such risk. The probability of including an infected individual person or animal can be calculated combining conditional probability and the binomial distribution.

Neurological disease in man following administration of suckling mouse brain antirabies vaccine.

In Latin America, suckling mouse brain (SMB) vaccine has become the most commonly used vaccine for immunization of both man and animals against rabies. This vaccine is highly immunogenic, is relatively economical and easy to produce, and is believed to be free of the immunoencephalitogenic factor. From 1964 to the end of 1969, there were 40 reported cases of neurological disease following administration of SMB vaccine, 32 of which met the criteria for inclusion in this report. These 32 cases occurred in 8 different countries. In contrast to neurological disease following the administration of other types of nervous tissue vaccine, the majority of the cases following vaccination with SMB vaccine had a Guillain-Barré-type syndrome with peripheral nervous system involvement and a higher case-fatality rate. The causative agent has not been demonstrated. Modifications in the production and handling of the vaccine may be producing changes that are responsible.