STUDIES OF THE USE OF DIFFERENT INACTIVATED SMALLPOX VACCINES.
Abstract
Inactivated vaccinia virus vaccines can be made in different ways and several methods are available. In our hands the use of the chorio-allantoic membrane of the chick was shown to be satisfactory. Estimation of titre of neutralizing antibodies resulted in a method described as the 50% neutralization method (NT-50) and is preferred over pock counting on the chorio-allantoic membrane. Experiments on rabbits demonstrated the value of inactivated vaccinia egg vaccine but also revealed the difficulties concerned in reading the skin reaction following vaccination with normal standard live vaccinia vaccine by scarification on rabbit skin. As a result of different investigations with inactivated small-pox vaccine in human volunteers, a delayed hypersensitivity test of the skin was developed which can give useful information concerning the immunity against vaccinia. The test proved to be of more value than an estimation of titre of neutralizing antibody. The boosting effect of small doses of inactivated small-pox vaccine was used in the revaccination of older people when the previous vaccination had taken place long ago. If the period of time after the last vaccination exceeds 15 years or more, intracutaneous injection of a small dose of inactivated small-pox vaccine (0.2 ml), three weeks before the revaccination, may prevent a possible severe clinical reaction following this revaccination. As with inactivated polio vaccine at least four injections of inactivated small-pox vaccine are necessary to obtain sufficient immunity. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1968
- Accession Number
- AD0834875
Entities
People
- B. J. W. Beunders