The U.S. government has marked another significant milestone in its effort to better protect Americans against the Zika virus: the first ASPR-supported Zika vaccine has begun a Phase I clinical trial, which will evaluate the general safety of the vaccine in people and provide information on the ways that different doses of the vaccine impact immune response.

The investigational vaccine developed by Moderna Therapeutics of Cambridge, Massachusetts, utilizes a novel messenger RNA (mRNA) vaccine technology. Moderna’s vaccine consists of a small piece of mRNA that when injected into a person’s arm muscle will direct the expression of specific proteins from the Zika virus that have been shown to create an immune response in various animal models. The body then mounts an immune response to these proteins, which will then provide protection to the individual from Zika virus infection and subsequent disease or transmission of the virus to others. Moderna’s vaccine does not contain infectious Zika virus and will not cause an individual to contract Zika disease.

ASPR’s Biomedical Advanced Research and Development Authority, or BARDA, provided Moderna $52.4 million in 2016 to support the development of this vaccine candidate, including conducting a Phase 1 clinical trial, as well as advancing toxicology studies, vaccine formulation and manufacturing scale-up for larger Phase 2/3 efficacy trials. Depending upon the success of the vaccine candidate and available funding, BARDA may provide up to $125.5 million to Moderna to support the advanced development of their Zika vaccine candidate.

BARDA’s collaboration with Moderna on a Zika vaccine also advances a major initiative to support new vaccine production platforms that will improve the efficiency and reduce the timeline to develop vaccines for biodefense threats and emerging infectious diseases. Platform technologies, such as the mRNA approach, can provide flexible and rapid response and have many advantages with potential to revolutionize the way vaccines and therapeutics are produced for known and newly emerging threats.

To improve our chances of having a vaccine available that provides protection to people and halts the spread of the Zika virus, BARDA is supporting this and several other Zika vaccine candidates.

The types of Zika vaccine candidates the U.S. government is supporting are:

• mRNA-based: the Moderna vaccine candidate utilizes a novel technology and vaccine production platform that also could be useful for other biodefense threats and infectious diseases;
• DNA-based: the NIH is currently in Phase 1 trials with two DNA-based vaccine candidates. This type of vaccine may have application in other public health emergencies to help protect the public against newly emerging viruses;
• Inactivated whole virus-based: several candidates are currently being evaluated by NIH, DoD and BARDA at this time. This type of vaccine is based on the same technology that was used to license a vaccine for Japanese encephalitis; and,
• Live-attenuated chimeric-based: this technology is being supported by the NIH and uses a platform that currently is in Phase 3 trials for dengue virus.

We don’t yet know which vaccine strategy might prove to be most successful, but the history of drug development teaches us that we need multiple shots on goal if we want to beat Zika.

It is also worth noting that there were no vaccine candidates for Zika around a year ago. By November 2016, there were more than a dozen approaches to Zika vaccines being evaluated in the U.S. alone. Some of these also have made great progress in development toward clinical trials. Our goal is to have a vaccine in 2018 that can provide protection to at-risk populations under an appropriate regulatory mechanism, and vaccines that are approved and available for broad use in 2020.