GeoVax Provides Update on its Zika Vaccine Development

ATLANTA, GA--(Marketwired - Sep 18, 2017) - GeoVax Labs, Inc. (OTCQB: GOVX), a biotechnology company developing human vaccines, announced that its Chief Scientific Officer, Farshad Guirakhoo, PhD, is delivering an updated presentation of results from studies of GeoVax's NS-1 based Zika vaccine. Dr. Guirakhoo will deliver the talk, entitled "Development of a Novel Vaccine for Zika," today during the 11^th Vaccine Congress in San Diego, CA.

Dr. Guirakhoo is presenting research showing that a single intramuscular dose of GeoVax's Zika vaccine gave 100% protection in normal mice challenged with a lethal dose of Zika virus (ZIKV) delivered directly into the brain. This is i) the only Zika vaccine in development which is based on the NS1 protein, and ii) the first report of single-dose full protection against ZIKV using an immunocompetent lethal mouse challenge model.

The vaccine was tested at the Centers for Disease Control and Prevention (CDC) in Ft. Collins, CO. with funding by a grant from the CDC. In the study, outbred immunocompetent mice were exposed to a lethal challenge dose of ZIKV delivered directly into the brain. A single dose of GeoVax's NS1 vaccine candidate protected 100% of vaccinated animals. In contrast, all sham-immunized control animals died within ~7 days.

GeoVax selected the ZIKV NS1 antigen as the target immunogen for its vaccine, as recent findings in mice and non-human primates indicate a potential risk of disease enhancement using traditional Zika vaccine approaches based on the ZIKV envelope proteins. This "Antibody Dependent Enhancement (ADE) of infection" phenomena, previously shown to enhance dengue infections in humans⁽¹⁾, is now expected to potentially include ZIKV, dengue virus' closest relative. Results of a new study performed in Rhesus Macaques provides in vivo evidence that prior exposure to ZIKV infection can enhance dengue infections⁽²⁾ should the individual be subsequently infected by a dengue carrying mosquito. An NS1-based vaccine avoids the ADE risk since this protein is not packaged into the virus particles, and is not involved in ADE. This approach holds the promise for a highly effective Zika vaccine, that is safer than enveloped-based vaccines for those who live in areas where the Zika virus co-circulates with other flaviviruses such as dengue.

(1) Halstead, S. B. Pathogenesis of dengue: challenges to molecular biology. Science 239, 476-481 (1988)
(2) George et al, Scientific Reports 7, Article number: 10498 (2017)

About GeoVax

GeoVax Labs, Inc. is a clinical-stage biotechnology company developing human vaccines against infectious diseases using its Modified Vaccinia Ankara-Virus Like Particles (MVA-VLP) vaccine platform. The Company's development programs are focused on vaccines against HIV, Zika, hemorrhagic fever viruses (Ebola, Sudan, Marburg, Lassa) and malaria. GeoVax also is evaluating the use of its MVA-VLP platform in cancer immunotherapy, and for therapeutic use in chronic Hepatitis B infections. GeoVax's vaccine platform supports in vivo production of non-infectious VLPs from the cells of the very person receiving the vaccine. The production of VLPs in the person being vaccinated mimics virus production in a natural infection, stimulating both the humoral and cellular arms of the immune system to recognize, prevent, and control the target infection. For more information, visit www.geovax.com.

Forward-Looking Statements

Certain statements in this document are "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act. These statements are based on management's current expectations and are subject to uncertainty and changes in circumstances. Actual results may differ materially from those included in these statements due to a variety of factors, including whether: GeoVax can develop and manufacture its vaccines with the desired characteristics in a timely manner, GeoVax's vaccines will be safe for human use, GeoVax's vaccines will effectively prevent targeted infections in humans, GeoVax's vaccines will receive regulatory approvals necessary to be licensed and marketed, GeoVax raises required capital to complete vaccine development, there is development of competitive products that may be more effective or easier to use than GeoVax's products, GeoVax will be able to enter into favorable manufacturing and distribution agreements, and other factors, over which GeoVax has no control. GeoVax assumes no obligation to update these forward-looking statements, and does not intend to do so. More information about these factors is contained in GeoVax's filings with the Securities and Exchange Commission including those set forth at "Risk Factors" in GeoVax's Form 10-K.