Active immunization against poliomyelitis

Abstract

Hammon has just told you of some of the beneficial aspects, as well as some of the drawbacks, of gamma globulin (immune serum globulin) therapy, and I am sure that we most certainly agree with Dr. Hammon that immune serum globulin is not the final answer to the problem of long-term protection against poliomyelitis. The various shortcomings of immune serum globulin therapy have been discussed in considerable detail elsewhere/so that it is not necessary to discuss that phase of the problem at this time. Without doubt, the only approach to the poliomyelitis problem is to bend every effort to develop a safe and practical immunizing agent: a vaccine that will give long-lasting protection against the disease. To that end, we have the possibility of developing either a killed preparation or a living attenuated virus vaccine. Other investigators, such as Morgan, 2 have shown that monkeys inoculated repeatedly (12 to 15 times) with inactivated poliomyelitis virus-infected spinal cord tissue of monkeys treated with formalin-produce neutralizing antibody in fairly high titer and show measurable resistance to challenge with virulent virus. Recently, Howe 3 has reported some preliminary trials carried out in man with inactivated vaccines prepared from spinal cords of infected monkeys. Killed vaccines of this type, prepared from infected central nervous tissue, may be dismissed immediately from practical consideration, first, because poliomyelitis virus cannot be concentrated and readily freed of the nervous tissue components that are responsible for producing allergic encephalitis; second, it is doubtful