Vaxart, a clinical stage biotechnology company developing oral recombinant vaccines that are administered by tablet rather than by injection, has initiated preclinical testing of an oral vaccine for Zika virus. With no available vaccine or treatment modalities, the World Health Organization (WHO) recently declared Zika virus an international public health emergency.
Vaxart’s vaccine platform enables delivery of recombinant vaccines using a convenient room temperature-stable tablet that can be shipped and stored without refrigeration, and is ideally suited for viruses such as Zika. In a phase I study with an H1 influenza vaccine based on the same platform, the results of which were published recently in The Lancet Infectious Diseases, the tablet vaccine generated robust and broad immune responses against the target virus.
“Vaxart is responding to the global call-to-action to develop a Zika vaccine given the rapid spread of the disease and the devastating impact on pregnant women and infants,” said Vaxart chief executive officer Wouter Latour, M.D. “A tablet vaccine for Zika virus could offer tremendous public health benefits for affected and at-risk regions. We are engaging with government agencies, industry partners and NGOs, and intend to work together with them to develop a potential vaccine modality against Zika virus.”
Zika virus is a mosquito-borne disease that causes mild flu-like symptoms in most people. In pregnant women it may be linked to an increased rate of microencephaly, a neurodevelopmental disorder characterized by a smaller-than-normal head and brain size. Life expectancy for individuals with microencephaly is reduced and the prognosis for normal brain function is poor. The virus may also be linked to an uncommon autoimmune disorder of the nervous system called Guillain-Barré syndrome.
“For public health emergencies, such as Zika virus, a tablet vaccine could provide important advantages in distribution, administration and immunization” said Vaxart Chief Scientific Officer Sean Tucker, Ph.D. “Of note, in a recent phase I study our H1 influenza tablet vaccine—which is based on the same oral platform—generated impressive antibody and T-cell responses after just one dose.”
Prior to 2015, Zika virus outbreaks occurred in areas of Africa, Southeast Asia, and the Pacific Islands. In May 2015, the Pan American Health Organization (PAHO) issued an alert regarding the first confirmed Zika virus infections in Brazil. Currently, outbreaks are occurring in many countries. Local mosquito-borne transmission of Zika virus has been reported in the Commonwealth of Puerto Rico, the U.S. Virgin Islands and American Samoa. No local mosquito-borne Zika virus disease cases have been reported in the United States, but there have been travel-related cases.