ATLANTA, GA--(Marketwired - Jun 5, 2017) -  GeoVax Labs, Inc. (OTCQB: GOVX), a biotechnology company developing human vaccines, presented research showing that a single dose of its Zika vaccine gave 100% protection in mice challenged with a lethal dose of Zika virus (ZIKV). This is the first report of i) a Zika vaccine based on the ZIKV NS1 protein, and ii) single-dose protection against ZIKV using an immunocompetent lethal mouse challenge model.

Details of the study were presented on June 4 by Farshad Guirakhoo, PhD, GeoVax's Chief Scientific Officer, at the American Society for Microbiology (ASM) Microbe conference in New Orleans. ASM Microbe 2017 showcases the best microbial sciences in the world including seven tracks, 500+ sessions and 575+ speakers from 96 countries covering topics from basic science to translation and application.

The vaccine was tested at the Centers for Disease Control and Prevention (CDC) in Ft. Collins, Colorado 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, 80-90% of sham-immunized control animals died within 7-10 days.

GeoVax selected the ZIKV NS1 antigen as the target immunogen for its vaccine, as recent findings 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 has been shown between ZIKV and related flaviviruses, such as West Nile and dengue, in both in vitro and in vivo studies. Mice given dengue or West Nile antibodies were more likely to die in the 2 weeks after the ZIKV infection than mice without these antibodies. 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, yet safer Zika vaccine for humans who live in the areas where the Zika virus co-circulates with other flaviviruses.

An NS1-based vaccine could also limit or block transmission of ZIKV in its mosquito vector. The NS1 protein is abundantly produced by flaviviruses in infected hosts and is picked up together with the virus after the mosquito takes a blood meal from humans. The NS1 proteins interfere with the innate immune system of the mosquito, evolved to fight foreign pathogens, allowing the flavivirus to replicate and disseminate in mosquitoes. Therefore, a vaccine that can induce effective antibodies to NS1 and disable its function has the potential to reduce growth and transmission of ZIKV in its mosquito vector. This could enhance vaccine effectiveness in endemic areas by blocking the virus transmission from infected individuals to other members of the community.

Zika virus disease is a rapidly spreading, emerging infectious disease transmitted by mosquitoes. The rapid spread of ZIKV, its association with abnormal fetal brain development, and lack of a preventive vaccine constitute a global health emergency. As of May 9, 2017, there have been 1,845 and 3,795 cases of pregnant women with evidence of ZIKV infection in the US and US territories, respectively. Seventy-two infants were born in the US alone with ZIKV related birth defects. Protection against mosquito bites and vector control remain the key preventive measures currently available to fight ZIKV infections. ZIKV belongs to the flaviviridae family, which also include dengue, West Nile and yellow fever viruses. For more information about ZIKV, visit

About GeoVax

GeoVax Labs, Inc. is a clinical-stage biotechnology company developing human vaccines against infectious diseases using its MVA-VLP vaccine platform. The Company's development programs are focused on preventive vaccines against HIV, Zika Virus, hemorrhagic fever viruses (Ebola, Sudan, Marburg, and Lassa), and malaria, as well as therapeutic vaccines for chronic Hepatitis B infections and cancers. GeoVax's vaccine platform supports in vivo production of non-infectious VLPs from the cells of the very person receiving the vaccine, mimicking 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

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.

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Robert T. McNally, Ph.D.
GeoVax Labs, Inc.