Skin patch delivery of a SARS-CoV-2 spike DNA vaccine produces broad neutralising antibody responses

The ongoing SARS-CoV-2 pandemic continues to be a major health burden globally, especially in resource-limited areas. Continued research into more effective and accessible vaccines is required to reduce the burden of disease. Here, we use an emerging vaccine delivery system, the high-density microarray patch (HD-MAP) to deliver a plasmid DNA vaccine (Delta 6P) encoding for the SARS-CoV-2 spike protein. HD-MAP delivery of this vaccine resulted in robust IgG responses in mice against multiple domains of the spike protein. The cellular response to vaccination was also measured, and comparative analysis showed that relative to intramuscular vaccination, HD-MAP vaccination elicited spike-specific CD4⁺ T and CD8⁺ T cell responses that were largely comparable, but the number of polyfunctional CD4⁺ T cells was higher in the HD-MAP group. Collectively, this work suggests that HD-MAP delivery of the Delta 6P vaccine is effective against SARS-CoV-2, warranting further investigation.