# Improved efficacy of an influenza DNA vaccine through high-density microarray patch delivery

## TL;DR

A new delivery method for DNA vaccines improves their effectiveness against influenza, offering better protection than traditional injections.

## Contribution

High-density microarray patch delivery significantly enhances DNA vaccine immunogenicity compared to intramuscular injection.

## Key findings

- HD-MAP delivery resulted in earlier and higher expression of a luciferase reporter construct compared to intramuscular injection.
- HD-MAP induced strong HA-specific IgG responses, while intramuscular delivery did not.
- HD-MAP-vaccinated mice were fully protected from weight loss during H1N1 challenge, whereas 50% of intramuscularly vaccinated mice were not.

## Abstract

Pandemic preparedness requires vaccine platforms that are fast to produce, thermostable and suitable for broad deployment. DNA vaccines are well suited to this task but have historically suffered from poor immunogenicity when delivered by conventional intramuscular (IM) injection. Here, we evaluated high-density microarray patch (HD-MAP) delivery of a DNA vaccine encoding the influenza A/California/01/2009 (H1N1pdm09) haemagglutinin (HA) antigen. In vivo imaging of a luciferase reporter construct demonstrated earlier and higher expression following HD-MAP application compared to IM injection. HD-MAP delivery of the HA vaccine induced strong HA-specific IgG responses, whereas IM delivery did not. Upon challenge with a homologous H1N1 virus, all HD-MAP-vaccinated mice were protected from weight loss, while 50% of intramuscularly vaccinated mice met humane endpoints. These findings support the use of HD-MAPs to overcome delivery limitations of DNA vaccines and enhance their utility for future outbreak and pandemic response.