About Zika Virus. Zika disease is a rapidly spreading emerging infection caused by the Zika virus (ZIKV) and is linked to microcephaly in infants and Guillain-Barre syndrome (a neurodegenerative disease) in adults. ZIKV is a member of the Flaviviridae family, which includes medically important pathogens such as dengue fever, yellow fever, Japanese encephalitis, tick-borne encephalitis, and West Nile viruses. ZIKV, which was first discovered in 1947 in the Zika forest of Uganda, was considered only a minor public health concern for 60 years. Recently, with its appearance and rapid spread in the Americas, it has emerged as a serious threat with pandemic potential. Symptoms of Zika infection have historically been mild. In the recent epidemic, however, an alarming association between ZIKV infection and fetal brain abnormalities including microcephaly were suspected and later confirmed by strong scientific evidence. No approved preventive or therapeutic products are currently available to fight the Zika epidemic. Public health officials recommend avoiding exposure to ZIKV, delaying pregnancy, and following basic supportive care (fluids, rest, and acetaminophen) after infection. A vaccine is urgently needed to prevent a Zika pandemic.
Our Vaccine. To address the unmet need for a ZIKV vaccine, we are developing novel vaccine candidates constructed in our MVA-VLP vector platform, which has already shown great promise in our HIV and Ebola vaccines., The GeoVax vaccine combines a highly potent, yet safe, replication deficient viral vector (MVA) to express protective antigens of ZIKV that assemble into VLPs within the vaccinated person. Advantages of MVA-VLPs include efficient stimulation of highly durable antibody responses with neutralizing and Fc-mediated mechanisms of protection; enhanced cross-protection by the elicitation of antigen specific T cells as well as antibody; and stimulation of the innate immune response without the need for an adjuvant. Also, MVA has an outstanding safety record, which is particularly important given the need to include women of child bearing age, and newborns among those being vaccinated. We expect these features to yield a safe and highly effective vaccine that is well suited to provide potent and durable immunity against ZIKV infection.
Our primary collaboration on the development of a ZIKV vaccine is with the University of Georgia (UGA) to perform mouse studies. We have also collaborated with the US Centers for Disease Control (CDC) to develop a lethal challenge model in mice to test our vaccine candidates. We have demonstrated 100% protection in mice against a lethal challenge after a single dose vaccination. ZIKV and reagents will be supplied by the University of Texas Medical Branch (UTMB). Working with multiple collaborators and multiple candidate vaccines, we will manage risk by providing multiple paths toward the selection of the best vaccine candidate.