Date: 6/16/2008 6:30:00 AM

SAN DIEGO, June 16 /PRNewswire-FirstCall/ -- Vical Incorporated (Nasdaq: VICL) announced today the publication of results demonstrating that pandemic influenza DNA vaccines formulated with the company's patented Vaxfectin(R) adjuvant provided complete protection of mice and ferrets against lethal challenge with a highly pathogenic strain of H5N1 influenza virus. The publication of the data in the June 15 issue of The Journal of Infectious Diseases (JID)(1) expands previously reported results supporting human clinical testing of the vaccine candidates.

"We believe DNA vaccines offer significant advantages over conventional approaches," said Vijay B. Samant, Vical's President and Chief Executive Officer. "The publication of our pandemic influenza vaccine animal challenge data in a peer-reviewed scientific journal illustrates the approaches we are currently pursuing in our Phase 1 trial, and we look forward to releasing initial results from this study by August. This trial is also important because it marks the first time in humans for our Vaxfectin(R) adjuvant, which has potential applications with both DNA vaccines and conventional protein- based vaccines."

DNA vaccines can be adapted quickly to target emerging strains of influenza, manufactured in a few weeks in generic fermentation equipment, and stored for extended periods of time.

    Highlights of the JID article include:

     * A single injection of the company's three-component DNA vaccine
       provided complete protection from death and disease in ferrets against
       lethal challenge with the A/Vietnam/1203/04 strain of H5N1 influenza
       virus.
     * The three-component vaccine significantly decreased viral shedding in
       ferrets.  Reducing viral shedding, which is the primary cause of
       disease transmission, could be critically important in limiting the
       scope of a pandemic.
     * A one-component H5 version of Vical's vaccine provided complete
       protection from death in mice against lethal challenge with the H5N1
       influenza virus. A prior Vical publication showed that one-component H3
       or H1 vaccines also provided complete protection from death in mice
       against lethal challenge with H3N2 or H1N1 strains of influenza virus.

Vical's three-component pandemic influenza DNA vaccine candidate targets two "conserved" and one "variable" influenza virus proteins. Vical's one- component DNA vaccine candidate targets only the variable influenza virus protein.

The company is currently conducting a double-blind, placebo-controlled Phase 1 trial of three-component and one-component Vaxfectin(R)-formulated DNA pandemic influenza vaccines to evaluate safety, tolerability and immune responses in approximately 100 healthy volunteers. Vical has completed enrollment in the Phase 1 trial and expects to release initial results by August.

About Vical

Vical researches and develops biopharmaceutical products based on its patented DNA delivery technologies for the prevention and treatment of serious or life-threatening diseases. Potential applications of the company's DNA delivery technology include DNA vaccines for infectious diseases or cancer, in which the expressed protein is an immunogen; cancer immunotherapeutics, in which the expressed protein is an immune system stimulant; and cardiovascular therapies, in which the expressed protein is an angiogenic growth factor. The company is developing certain infectious disease vaccines and cancer therapeutics internally. In addition, the company collaborates with major pharmaceutical companies and biotechnology companies that give it access to complementary technologies or greater resources. These strategic partnerships provide the company with mutually beneficial opportunities to expand its product pipeline and address significant unmet medical needs. Additional information on Vical is available at http://www.vical.com.

This press release contains forward-looking statements subject to risks and uncertainties that could cause actual results to differ materially from those projected, including: whether Vical or others will continue development of the Vaxfectin(R)-formulated pandemic influenza DNA vaccine candidates; whether the vaccine candidates will be safe and tolerable, or effective in eliciting immune responses; whether H5N1 or other strains of influenza will emerge as pandemic threats; whether the Vaxfectin(R) adjuvant will be applied with other vaccine candidates; whether results from the pandemic influenza vaccine studies will be predictive of results in other vaccine applications; whether the company's DNA vaccine candidates will be effective in protecting humans against H5N1 or other strains of influenza or in reducing viral shedding; whether results in mouse and ferret studies will be predictive of results in human studies; whether the influenza vaccine candidates or any other product candidates will be shown to be safe and effective in clinical trials; the timing, nature and cost of clinical trials; whether Vical or its collaborative partners will seek or gain approval to market the influenza vaccine or any other product candidates; whether Vical or its collaborative partners will succeed in marketing an influenza vaccine or any other product candidates; and additional risks set forth in the company's filings with the Securities and Exchange Commission. These forward-looking statements represent the company's judgment as of the date of this release. The company disclaims, however, any intent or obligation to update these forward-looking statements.

(1) Lalor PA et al. Plasmid DNA-Based Vaccines Protect Mice and Ferrets against Lethal Challenge with A/Vietnam/1203/04 (H5N1) Influenza Virus. J Infect Dis 2008; 197:1643-52.

     Contact:  Alan R. Engbring
               (858) 646-1127
               Website:  http://www.vical.com


SOURCE  Vical Incorporated
    -0-                             06/16/2008
    /CONTACT:  Alan R. Engbring, +1-858-646-1127/
    /Web site:  http://www.vical.com/
    (VICL)

CO:  Vical Incorporated
ST:  California
IN:  MTC HEA
SU:  SVY