Researchers may have found a vaccine for the Zika virus, also known as ZIKV. There is currently no vaccine approved for use on humans. The development of a working vaccine is currently considered a global health priority. A new study, published in the journal Nature, suggests two possible vaccine techniques for ZIKV. Both of the new vaccines completely immunized mice to the virus. The authors are hopeful that future trials will continue to be successful.
ZIKV is a flavivirus, the same family that contains yellow fever and the West Nile virus. The Zika virus is spread through mosquito bites and sexual contact. The symptoms are generally mild and resolve on their own. If a pregnant woman becomes infected, however, the virus causes serious birth defects such as microcephaly and intrauterine growth restriction. There is no current treatment. Since vaccines for other viruses in the flavivirus family had already been developed, the researchers used that knowledge as the foundation for their study.
The experimenters tested two viruses. One was a DNA vaccine and the other was a vaccine using a purified, inactivated virus. The researchers vaccinated mice and then exposed them to ZIKV four weeks later. ZIKV causes birth defects in mice, just like in humans. The vaccinated mice didn’t become infected. A different group of mice wasn’t exposed to the virus for eight weeks. This second group also avoided infection.
The Zika virus epidemic has affected 61 countries so far, according to the World Health Organization. Thanks to philanthropic fundraising, researchers are getting close to developing a viable human vaccine. Both vaccines tested on mice were effective and safe. The vaccines have yet to be tested on humans but the authors stated in their paper that “the development of a ZIKV vaccine for humans will likely be readily achievable.” Further clinical trials for these two vaccine candidates will start later in the year.
Rafael A. Larocca et al. Vaccine protection against Zika virus from Brazil. Nature (2016).