Addressing The Challenges Of Vaccines And Intradermal Delivery

By John P. Vasilakos, Ph.D.

Well before the outbreak of COVID-19, vaccines were a vital tool in promoting public health. The importance of vaccines has become even more apparent as we collectively observe the race to develop a vaccine and wait for good news. The absence of a COVID-19 vaccine predictably resulted in prolonged, deleterious global health, economic, and social outcomes. The pandemic has exposed industry limitations in the development of vaccines, such as the ability to scale-up vaccine supplies quickly. In response to this crisis, the pharmaceutical and healthcare industries should react by both reaffirming the importance of vaccines and by exploring ways to improve vaccine development and delivery.

To make effective vaccines, multiple challenges must be overcome. A vaccine can be suboptimal because of the vaccine itself. The vaccine can also be suboptimal if there are flaws in the selection, compatibility, or manufacture in any of its three major components: the antigen, the adjuvant, and the formulation. The antigen provides a template for the immune system, hence teaching the immune system what specific pathogen it needs to respond to when it encounters the pathogen. The adjuvant enhances or helps the immune system respond to the antigen. The formulation holds the antigen and adjuvant together and gives the vaccine stability. In recent years, there has been a tremendous focus on the physical and chemical properties of vaccines. This includes important advances in the understanding of complex adjuvants along with a resurgent interest in vaccine formulations. There is still progress to be made, but the amount of discovery in this field over the past few decades is encouraging.

In addition to the considerations taken to optimize the three key vaccine components, the vaccine delivery method must also be taken into consideration if optimal vaccine performance is to be achieved. The efficacy of a vaccine can be limited by the manner in which it is delivered to the body. Therefore, the delivery system or device may play an important role in improving the efficacy of the vaccine.

This article considers six shortcomings in the way vaccines are developed and delivered. Addressing these deficiencies could improve both the efficacy and accessibility of vaccines around the world.