A group of researchers led by a team from UCLA have developed a vaccine that, in mice, is effective against the effects of anthrax, plague, and tularemia – three pathogens that might be used in a bioterror attack. The findings are published in Scientific Reports.
There are currently no licensed vaccines for tularemia or the plague. There is one against anthrax but it has severe side effects and a lengthy immunization schedule. The team used molecular engineering to produce a vaccine that was effective, safe, and non-toxic.
“Relying on currently available antibiotics to counter an intentional outbreak of anthrax, plague or tularemia is not a pragmatic public health plan – vaccines offer the only practical protection,” senior author Dr Marcus Horwitz said in a statement.
The researchers started with a weakened version of an unlicensed tularemia vaccine, which is toxic to humans. To make it safe, they deleted one gene from the original bacterial version, which took away its toxicity. They then repeated the procedure for the other two pathogens. The team was able to then deliver the vaccine using the common “single vector” approach.
“Vaccines utilizing a single vector that could be administered concurrently and protect against all three pathogens would be more acceptable to people than multiple unrelated vaccines requiring different immunization schedules, and be less costly because they would be simpler to manufacture,” explained Horwitz.
The researchers delivered the vaccine either with an injection or with a nasal spray. Four to six weeks after immunization, the mice in the experiment were exposed to lethal doses of the three pathogens. The new vaccine protected the mice.
The team also compared their creation to the commercially available anthrax vaccine and found that it was far superior. It was also more potent than the unlicensed tularemia vaccine when it was administered through the nose. While two injections protected about half of the mice (like the old tularemia vaccine), inhalation of the vaccines two or three times protected all the mice exposed to the pathogens.
The vaccine will be improved and then tested again for safety and efficacy as required by the US Food and Drug Administration. Then the team will hopefully move to human testing. According to US government agencies, these three pathogens are the most likely to be used in a bioterror attack.