This is my last blog post for 2021 and one would have hoped that by now, we would be talking about something other than COVID-19. I think we can all unanimously agree that 2020 was a bit of a write-off and certainly I know that a lot of my patients (and myself!) were hoping that 2021 would be the year that we could all move on.
However, we have reached the twelfth month of 2021 and at the time of writing, Europe is in the midst of its fourth wave, riots and protests are sprouting up on the continent due to the reinstitution of restrictions and the WHO are urging those still unvaccinated to get vaccinated with dire predictions if they do not. We do know that the Spanish flu pandemic of 1918-19 occurred in three, or possibly four waves before it died down and that was the last major lethal pandemic.
We endlessly debate amongst ourselves (family, friends, patients) about the arguments for and against vaccination. My entire family have received their vaccinations and the only that hasn’t yet is under 12y. Whatever a person’s individual reason for not getting vaccinated, it was interesting to hear in the New Scientist about two new methods of vaccine delivery that may improve the immune response to the vaccine.
We use patch tests all the time in dermatology. Patch testing is used to see if there is any element of contact allergy in the context of eczema and involves measured doses of allergens held onto the skin by a patch or disc for 48 hours to see if it causes an eczema reaction. The patches are then removed at 48 hours but the skin is continued to be observed for a further 48 hours (no washing of the back!) to see if a further reaction develops (see the thumbnail for this post).
The patch being investigated for delivery of the Covid vaccine is 1cm wide and dotted with 5000 0.25mm plastic spikes which are coated with dried vaccine. The patch is applied and pressed onto the skin, delivering the vaccine into the upper layers of the skin.
The team who developed the patch have spent years developing skin patches that can deliver other vaccines such as influenza and polio. They found that the patch vaccine created a robust immune response in mice which was superior to that from the traditional intradermal injection.
[McMillan CLD, Choo JJY, Idris A et al. Complete protection by a single-dose skin patch-delivered SARS-CoV-2 spike vaccine Sci Adv 2021;44]
Obviously if this study is replicated, the benefits are huge. We know that current vaccines in use have issues with vaccine transport and delivery which is all fair and well in developed countries. However in countries such as Africa, a thermostable, easy to administer or even self administer vaccine would have massive beneficial implications.
This study looked at the application of suction after intradermal injection of a Covid DNA vaccine into rats.
[Lallow EO, Jhumur NC, Kudchodkar SB et al. Novel suction-based in vivo cutaneous DNA transfection platform. 2021 Sci Adv 2021; 45.]
Now the Covid vaccines we use currently are all RNA vaccines. The authors look at DNA vaccines instead. These are much more stable than RNA vaccines upon injection but have lower efficacy. The application of suction (the equivalent pressure needed to extract a blackhead and similar to the cupping methods found in China and the Middle East) was found to induce rapid and efficient delivery of nucleic acids (the things that make DNA) into cells. The authors did not know why there was this benefit after suction.
The authors state that there was no tissue injury so suggest it is something that will be well tolerated in humans, it’s cheap and requires minimal training and could be used to treat diseases that require a rapid immunological response.
Well who knows? Things change so rapidly in the field of coronavirus. Let’s just hope by next Christmas, we are talking about something else!
Dr Sandy Flann, Consultant Dermatologist