There are multiple institutions working on a vaccine for SARS-Cov2 (Covid19) right now.
University of Pitt School of Medicine just announced an effective vaccine that is delivered just under the skin, intracutaneously, called micro-needle-array immunization. It works in animal models and is pending emergency FDA approval for accelerated human safety trials. This is a very important development because it is stable at room temperature stable and can easily be stored, transported around the world, and easily administered without a painful intramuscular injection. It also uses very low antigen levels and is therefore considered to be far safer than the Flu vaccine, which uses much higher quantities of flu virus antigen injected into the muscle rather than under the skin.
The vaccine technology uses a simple spike protein antigen to provoke the human body to produce an antibody response that will attack the spike protein on the virus. The spike protein is critical for this virus to enter and infect the cell. This is similar to how other successful viral vaccines work. The reason this vaccine could be developed so quickly is because the research scientists had worked specifically on the 2003 SARS-Cov1 outbreak and the MERS outbreak a decade later. So when the genome of the SARS-Cov2 (Covid19 disease) was shared by China in late January, the development of this specific vaccine could already get underway.
There is no clear time-frame that can be predicted to get this vaccine mass produced, but trials will begin as soon as the FDA grants approval. Then it will still likely take several months to prove efficacy and safety. Production will start ramping up once human trials are underway, in order to prepare for large scale distribution. It is estimated that around 45% of the population would need immunization in order to provide some basic herd immunity. That statistic adds up to tens of millions of vaccines, but in my estimation, if the most vulnerable could be prioritized, then we’d be able to safely return to our normal lives a bit sooner.
There is another vaccine already in human trials in China and the United States. This vaccine is an injectable (intramuscular) immunization designed to stimulate the production of IgG (immunoglobin) antibodies that are targeted against this virus. If successful, these IgG antibodies will destroy the virus and prevent Covid19 in those who’ve had the vaccine.
However, there are two other vaccines in development that are not injected into the muscle and that offer even more promising protection. There is the fully developed intracutaneous (micro needle array) vaccine mentioned above, and there is an oral vaccine that is near completion, by Migal Labs in Israel.
What I like about both oral and intracutaneous vaccinations is that the safety aspects are far less complex. They are lower risk, especially the intracutaneous vaccine, which consists of less than a scratch on the skin and has the added benefit of storing at room temperature and being easy to mass produce.
Both the intracutaneous and oral vaccines give better immunity because they provide mucosal IgA antibodies, which is what we get after a real infection, in addition to IgG. IgA prevents the pathogen from entering into the body, whereas IgG antibodies initially allow the pathogen to enter the body but effectively prevent systemic infection. It is extremely important to note that IgA antibodies will theoretically also be present in the respiratory and intestinal systems as a result of these two vaccine types, which should prevent viral replication in those systems and prevent spread of disease in asymptomatic individuals. Both scenarios prevent systemic infection but the injected vaccine permits the pathogen to exist in the mucosa to some extent, because injected vaccines can only produce IgG antibodies. An example of this is the Polio vaccine.
Polio used to be an oral live virus vaccine but was transitioned to an injected passive vaccine in the 1980s or thereabouts. Both vaccines work well, but the oral vaccine was discontinued in most places because it caused a wild type (real) infection in roughly 1 out of every 300,000 to 400,000 people who took the vaccine. This means that one unlucky person would actually get the Polio disease. For this reason we switched to injected vaccine, which cannot cause actual disease because the viral material is dead. However, when we changed over to exclusively using the injected vaccine we discovered that the virus was increasingly detected in the sewage (wastewater treatment systems). There wasn’t any upsurge in Polio cases, so this could only be explained by an increase in the replication of the virus in people’s guts, and therefore in our sewage. Since Polio is transmitted by fecal-oral route (poor sanitation and hygiene), this theoretically means that people who are not immunized against Polio may not be completely protected by herd immunity, as is the case with other vaccine use in society. Interestingly, there are reports of Covid19 being identified in the sewage/waste water in affected communities. This might be an argument for pursuing an oral vaccine against this Coronavirus.
So, my reason for explaining all of this is to make the case that the oral and probably the subcutaneous vaccine are both probably going to be more effective at creating comprehensive herd immunity due to offering IgA antibody protection. The IgA produced in response to taking the oral vaccine should also be present in the respiratory airways and therefore should protect the lungs from Covid19. And given that Migal Lab’s oral vaccine is already so close to completion, it may not be very long before clinical trials could theoretically start. As far as I understand, the clinical trials underway in China and the US are injected vaccine, for IgG immunity. It will be incredibly interesting to see the preliminary results as soon as they are published, as well as seeing the efficacy of both non-injectable vaccine trials once they get underway.
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Justin Groode MD | Patient Advocate Alliance LLC