Vaccine patch could protect against Zika virus

A simple-to-apply, needle-free vaccine patch could be used in future to protect people from the potentially deadly mosquito-borne Zika virus, with a new prototype combining a high-density microarray patch (HD-MAP) developed at The University of Queensland (UQ) and a vaccine developed at The University of Adelaide.

Zika virus generally causes a mild illness, but infection in pregnancy can lead to miscarriage and stillbirths or infants born with congenital malformations. According to The University of Adelaide’s Associate Professor Branka Grubor-Bauk, limited global surveillance shows Zika virus is active in at least 89 countries and territories but there is no currently licensed vaccine.

“We can change the way we combat Zika virus with the HD-MAP patch because it is an effective, pain-free, simple-to-apply and easy-to-store vaccination method,” said UQ alum Dr Danushka Wijesundara.

Wijesundara explained that HD-MAP delivers the vaccine to immune cells beneath the skin’s surface with thousands of tiny microprojections. In a preclinical trial published in the journal Molecular Therapy Nucleic Acids, the vaccine provided rapid protection against live Zika virus in mice, targeting a protein called NS1 which is crucial to the virus’s survival.

“This vaccine is unique because it targets a protein inside rather than outside of the virus, meaning it won’t enhance the symptoms of closely related viruses, such as dengue fever, in people who’ve been vaccinated,” Grubor-Bauk said. The result, Wijesundara added, is that the vaccine patch evoked T-cell responses that were about 270% higher than from a needle or syringe vaccine delivery.

UQ’s Dr David Muller said the microarray patch and the vaccine could have benefits beyond the ability to protect from Zika virus. “Because the protein we’re targeting plays a central role in replication in a virus family known as flaviviruses, there’s the potential to apply our approach to target other flaviviruses such as dengue or Japanese encephalitis,” he said.

“It could also deliver a vaccine mixture to target the whole family of viruses, providing greater protection.”

Muller added that the HD-MAP delivery platform offers vaccine stability at elevated temperatures, with the patch retaining vaccine potency when stored at 40°C for up to four weeks.

“This increases the reach of vaccines in low- and middle-income countries where refrigeration is challenging,” he said.

Image caption: The high-density microarray patch (HD-MAP).