Analysis of the Experience of Improving the Safety of Anti-Smallpox Vaccines

The epidemiological hazard of orthopoxviruses and the side effects of the used live vaccines are growing, raising the safety requirements for vaccination. The aim of this review was to analyze ways to improve the safety of smallpox vaccines. Biotechnological improvement of dermovaccines did not enhance safety to an acceptable level and caused the introduction of a large number of restrictions, contraindications, and eventually a ban on their use. The improvement of parenteral vaccines is dominated by the biotechnological trends of safety increment, which, combined with the immunological correction of the vaccination method (two-stage vaccination in Russia or multiple immunization abroad), contributed to achieving acceptable safety requirements for the third generation of smallpox vaccines. The failures of biotechnological improvement of dermovaccines led to the intensification of research on the development of third-generation oral vaccines of the TEOVac type, meeting the principles of safety and effectiveness, and further development of the immunological aspect of higher vaccination safety. The implementation of the immunological course for improving the safety of anti-smallpox vaccines was carried out through the development of oral mucosal vaccines and a two-stage vaccination method. Another problem with the specific prevention of smallpox is the high risk of complications after vaccination. A two-stage or two-fold method of vaccination with epidemiologically effective live vaccines is a universal solution for the relief of such complications. In the USA, a supply of homologous immunoglobulin has been created and chemotherapy drugs are being produced to relieve complications; in the Russian Federation, only the NIOX‑14 drug is currently licensed, and attempts are being made to compensate for the absence of homologous immunoglobulin with a heterologous purified drug. Thus, for Russia, the most effective and promising area for improving the safety of smallpox vaccines is immunological one: the development of a modern oral method of immunization, mucosal vaccines and a two-stage vaccination method. Abroad, the biotechnological trends in improvement of parenteral smallpox vaccines dominate, which is complemented by the immunological one.