Marc Grey
Are COVID Vaccines…Vaccines?
In a previous article, the 4 COVID vaccines coming to New Zealand were discussed in some detail. In this one, we examine some common questions that people have about these vaccines.
Firstly, because most of them are made via novel technology (in particular the use of genetic material) there are people saying, “they are not vaccines at all!” A more extreme version of this is: “they are genetic treatments, not vaccines”.
Secondly, there is considerable confusion generated by medical guidelines that say things like: “after vaccination, you should continue to social distance, wash hands etc”. And also: “after vaccination, you may still catch COVID, and could still infect others”. This has (quite reasonably) got folk asking: “what is the point of getting vaccinated then?” Or even: “Why are these vaccines not acting like vaccines?”
Are They Vaccines?
Looking at the first question, we really need to be clear what a vaccine is. The CDC says:
Vaccine: A product that stimulates a person’s immune system to produce immunity to a specific disease, protecting the person from that disease. Vaccines are usually administered through needle injections, but can also be administered by mouth or sprayed into the nose.
Wikipedia is similar, but uses the term “biological preparation” rather than product. The key factor is the ability to stimulate the body’s immune system to provide immunity. So that begs the question of whether the COVID vaccines do this. It seems they do (e.g Pfizer vaccine):
[…] the team led by Professor Ravindra K. Gupta has assessed the real-world immune responses following the vaccination against the SARS-CoV-2. The team measured 1) IFN-gamma (interferon-gamma) T cell responses, 2) both total IgG Spike/ IgG Spike RBD (receptor binding domain) and 3) neutralizing antibody responses to Spike in sera.
In fact, no vaccine will get through Phase 2 trials if they do not (e.g Pfizer again).
So it looks like these vaccines do in fact appear to be vaccines! Why then, are people saying otherwise? It appears that there is a misunderstanding about what a vaccine is – essentially re-defining in their minds that a vaccine must use all the virus concerned (or similar). In fact, there is no such prescription. Here are the various types (paraphrased):
- Inactivated – killed via chemicals or radiation
- Attenuated – cultivated in environment that disables virulent properties
- Toxoid – inactivated compounds produced by micro-organism
- Subunit – part of the micro-organism
- Conjugate – augment micro-organism by attaching toxin
- Heterotypic – a different micro-organism that provokes similar immune response
- RNA – RNA code for part of micro-organism
- Experimental – the others (including viral vector DNA)
So only two or three of them (‘inactive’, ‘attenuated’ and possibly ‘conjugate’) require the whole virus (the quote says micro-organism but we are interested in the virus case).
A less extreme variation of this mindset requires that at least some of the actual virus must be used. While it is a valid type of vaccine (‘subunit’ – note Novavax COVID vaccine is this type), it is (again) not the only type. In fact it is allowable to use by-products that an infecting agent makes and not the agent itself (‘toxoid’ not applicable to a virus), or even a different virus entirely (‘heterotypic’)!
So we get to ‘mRNA’ and ‘Viral DNA’ COVID vaccines, these contain RNA or DNA for part of the virus, and co-opt molecular machinery in some of our cells to produce part of the SARS-COV-2 virus. So these could be thought of as ‘kitset subunit’ vaccines! The mechanism is novel but the effect is the same.
Thus, it seems that claim “they are not vaccines at all” is not reasonable.
What about Catching and Passing On?
Moving on to the second question. To be able to understand what is happening here we need to revisit how vaccines work: The vaccine is administered, then the body’s immune system responds and various antibodies are made. Ideally, these persist for some time, and when the infecting virus enters the body, these antibodies are ready to fight it off. So in simple terms – the immune system is able to grab some antibodies ‘that were prepared earlier’. So does the body’s antibodies beat off the invasion? That is a statistical question; no vaccine is 100% effective, since the ‘quality’ of the antibodies are in part determined by the body’s reaction to the vaccine, which in turn is affected by how healthy it is (among other factors). The effectiveness of a vaccine is one of the things Phase 2 and Phase 3 trials determine (more on that later).
So the phrase “if you are vaccinated you may still get COVID” is really only saying that the vaccine is not 100% effective, it is not saying that it provides no immunity! However, the language could certainly be clearer.
The next area of consideration is “can you infect/pass on the virus if you are vaccinated”? It is highly desirable that a vaccine will result in any invading virus being destroyed quickly, so that it is not present in exhalations, sneezes etc. This is usually referred to as the vaccine having sterilising property. So do COVID vaccines not have this property? The answer appears to be that, due to the fact that the vaccine is being rolled out before the various trials (in particular Phase 3) are finished, they do not know yet if the vaccine has sterilising property. The CDC discuss this too. If we look at similar information for the influenza vaccine it mentions that having the ‘flu’ vaccine may protect people around you i.e ‘flu’ vaccine has sterilising property (interestingly, it also covers in depth that you can still get the ‘flu’ if you are vaccinated).
So in summary, it does appear that the COVID vaccines provide immunity, but the effectiveness percentage will be determined when the Phase 3 trials have been running for a while longer. In the meantime, there are estimates based on various trials (e.g around 90% for AstraZeneca COVID vaccine) and also actual data from the worldwide rollout (e.g Israel will be the one to watch as they will probably complete first).
The sterilising ability of the COVID vaccine is currently unknown, but – again – will be determined once the Phase 3 trials have been running for a while longer.
In the meantime, government health sites and vaccine data sheets are using careful language to avoid promising things that might turn out to be not true later on (and perhaps erring on the side of promising too little). Also, the general public are reading these statements much more care than they do with (say) the ‘flu’ vaccine, so are perhaps unaware that there are similar subjects covered in the datasheets for the ‘flu’ (and other vaccines).
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