Fears about vaccine side effects are one of the common reasons those who choose not to vaccinate use. Researchers at UConn and UC Davis recently developed a Safety Mechanism Assisted by the Repressor of Tetracycline or “SMART” virus vector for use in vaccines and therapeutics. Tetracycline is an antibiotic commonly prescribed to treat bacterial infections.
Paulo Verardi is a pathobiologist at UConn with the goal of making vaccines highly safe. “The most effective vaccines tend to be live replicating viruses, the so-called live attenuated vaccines. Vaccina virus, which is used as the smallpox vaccine is a good example While most vaccines are both safe and effective, those based on live viruses can cause problems in some people, so we designed a safety mechanism that can be activated by the administration of tetracycline by making minimal genetic modifications to vaccina virus.”
The smallpox vaccine is still given to members of the U.S. armed forces and first responders because of concerns of smallpox’s use as a bioweapon. The SMART vaccina virus allows the vaccine to be turned off if the person being vaccinated develops rare, but serious complications.
Researchers are hopeful that the Vaccina virus will be a valuable tool in the development of other vaccines besides smallpox. Because it is easy to propagate and doesn’t cause cancer, it is being discussed with AIDS and cancer vaccines for humans and rabies and fertility control vaccines for wildlife. Tests are also being done to see if vaccina virus can stimulate immune responses to cancers and kill cancer cells.
“This built-in safety mechanism has the potential to positively impact the development of the next generation, replication-competent VACV vaccines and therapeutic vectors, possibly allowing treatment of complications from vaccination or therapy to be as simple as standard tetracycline antibiotic treatment,” Verardi concludes.
While vaccine side effects are extremely rare, this technology will allow everyone to be vaccinated for life threatening diseases without worrying about potential side effects.