A Vaccine for Zika? Working on It!

The appearance of Zika virus in the United States has accelerated the search for a vaccine. Although experts believe that Zika virus will probably not be as severe a problem in the United States as it is in the tropics, it's still a major concern.

Similar to Dengue virus, which has never taken hold in cool climates, mosquito-spread Zika virus has the potential to cause considerable damage under the correct conditions. Its most publicized effect is microencephaly in children born to infected women. Most infected individuals will have no symptoms, or a very mild presentation. Some adults develop Guillain-Barre syndrome.

In the aptly-named article, "Prospects for a Zika Virus Vaccine," scientists from leading research institutes across the United States discuss efforts to protect the population here and abroad from this virus. With other nations affected much more severely, a safe and effective Zika virus vaccine is now a global health priority.

At this point, scientists have gleaned most data from preclinical proof-of-concept vaccine studies in mice and monkeys. The results indicate great potential for an effective vaccine.

Zika’s enveloped, positive-sense RNA structure is similar to known flaviviruses: dengue virus, West Nile virus, yellow fever virus, Japanese encephalitis virus (JEV), and tickborne encephalitis virus (TBEV). Vaccines are currently available for JEV and TBEV.

The fact that scientists have successfully developed effective flavivirus vaccines previously means that correlates and surrogates of protection are available, the researchers noted.

For Zika, nucleic acid vaccines, purified inactivated virus vaccines, and recombinant vector-based vaccines have been proven to provide protection in animal models.

Despite rapid-fire research into this virus, scientists still have many unanswered questions. The initial and most critical target population for a vaccine is pregnant women, the population in which the consequences of infection are most egregious. Additionally, questions remain about the duration of protection.

This study appears in the journal Immunity.

Reference

Barouch DH, Thomas SJ, Michael NL. Prospects for a Zika virus vaccine. Immunity. 2017;46(2):176-182.