A San Diego biotechnology firm said it hopes to begin human testing of its experimental anthrax vaccine by the year’s end.

Several companies and government researchers are racing to create a better anthrax vaccine than the one now available and manufactured by BioPort Inc. of Lansing, Michigan.

Vical Inc. executives presented data Monday that showed their novel DNA vaccine protected rabbits that inhaled anthrax with little side effect, building upon their successful work with mice.

Now the company hopes to convince the Food and Drug Administration (FDA) to allow it to test the two-injection regimen on a handful of people to prove the vaccine is safe.

It is highly unethical to purposely expose experiment volunteers to diseases like anthrax. So the FDA said it will approve some vaccines that protect at least two different animal species and prove safe in human experiments.

Vical head Vijay Samant said company executives and FDA officials are still discussing if the rabbit and mice data is strong enough to support human experiments or if tests on monkeys will be required first. An FDA spokesperson declined to comment on the talks.

Vical’s vaccine is created with genetic material of the anthrax bacterium that codes for two of the disease’s telltale proteins. The vaccine provokes a mild immune response and primes the body to defend against a more virulent attack.

A National Academy of Science study released last year said the approved vaccine works, but insisted a new vaccine is needed because BioPort’s requires six shots over 18 months plus an annual booster, and causes certain side effects.

Anthrax is an acute infectious disease caused by spore-forming bacteria. Five people were killed in 2001 by anthrax attacks by mail. It is considered to be a possible biological weapon that could be used against US troops.

Since those attacks, several biotech companies have been trying to develop a more effective vaccine - even if the potential markets appear small and confined to a government that shifts its bio-terrorism focus.

BioPort said experiments on its vaccine are underway to see if the number of injections can be cut in half while it works on a genetically engineered version that could be swallowed or snorted.

The US government, meanwhile, has created its own genetically engineered anthrax vaccine that promises to cut in half the six shots now needed for protection and awarded $22.5 million to a pair of biotechnology companies to begin testing it.

Burlingame-based VaxGen Inc. and Britain’s Avecia plan to test the experimental vaccine on people sometime this year to see if it is safe and, if so, to see if it provides protection against the deadly bacteria.