Active Immunization of Children Against Poliomyelitis with Formalin Inactivated Virus Suspension. ∗

Abstract

In previous communications 1 it was pointed out that definite immunity could be developed against the virus of poliomyelitis using virus rendered non-infective by formalin. However, the amount of formalin used produced considerable skin irritation. Since then it has been shown that virus suspensions inactivated with 0.1% formalin, at incubator temperature, were also antigenic for monkeys, and at the same time, gave practically no skin irritation. The majority of the animals showed both humoral immunity, as tested by the neutralizing power of the serum for the virus of poliomyelitis; and tissue immunity, that is resistance to intracerebral inoculation of active virus.

The inactivated antigen produced no reaction whatsoever, neither symptoms, temperature rise nor cerebrospinal fluid changes developed upon repeated inoculations of large doses given both intracerebrally and intraperitoneally, each dose representing the equivalent of thousands of infective doses of living virus. Moreover, during vaccination the animal suffered no untoward local or systemic reactions, so it was felt that the vaccine could be given to humans with perfect safety.

However, before giving it to children, it was deemed advisable to try it upon ourselves, not that we had any misgivings about the possibilities of infection, but rather to determine whether the vaccine produced any disagreeable local or general reactions. Accordingly, 6 volunteers from the Bureau of Laboratories, Department of Health, New York were given 5 cc. doses of a 10% virus suspension, inactivated with 0.1% formalin for 16 to 48 hours. Three were given one dose, two, 2 doses and the third, 3 doses.