Evolution of means and principles of smallpox vaccination

Abstract

There are several possible reasons for the return of smallpox as an endemic disease. For example, the possibility of maintaining smallpox virus in an active state in the corpses of the dead, buried in permafrost regions, or the evolutionary changes of orthopoxviruses with the appearance of more virulent strains. Since the eradication of smallpox, the requirements for smallpox vaccines have changed, leading to a change in the principles of smallpox vaccination. The purpose of the study is to review the evolution of means and principles of smallpox vaccination. For almost 200 years four generations of vaccine preparations have been developed. The first ones were the dermovaccines, i.e. the virus-containing detritus of calfskin. Then, chicken-embryo-skin cell cultures were used as a substrate for virus accumulation. The third generation were the vaccines based on vaccine strains at-tenuated by various methods. Fourth, DNA vaccines and subunit recombinant vaccines. One of the main contemporary principles of smallpox vaccination is safety (limited use of the vaccines of first and second generations, the development of next generations of vaccines, means and schemes of safe vaccination) while maintaining the requirements of efficiency equal to the existing vaccines. The replacement of epidemiologically tested vaccines with the third and fourth- generation drugs necessitated a comparative assessment of the protective efficacy and safety of new vaccines. It may be useful to carry out two-stage vaccination using inactivated or new safe nonreplicating the third and fourth generation vaccines at the first stage.

Keywords

• attenuated and recombinant strains
• vaccination
• vaccinia virus
• orthopoxviruses
• smallpox vaccine
• smallpox immunization