The Science behind Vaccines: How quickly can scientists create a vaccine, will they actually work?
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Due to the crisis that has come out of Covid-19, the processes by which vaccines are produced are being scrutinised more than ever before. Previously, vaccines were created but not seen as a frontline of defence for something as vital as the safety of the entire world. The onset of coronavirus has structurally shifted that calculus, making the productions of vaccines more important than ever. But how does one actually produce a vaccine, and what is the chance of it actually working. After all, after 30 years of trying, HIV still does not have a vaccine, let alone a cure.
It is fairly obvious that vaccines are not always going to be successful: on a purely numerical basis, most vaccines have to go through years upon years of testing, to look for potential side-effects and unintended consequences that could come back to haunt them in the long run, and get ultimately brought down by one of many hurdles in their way. This has made the vaccine production process one that takes place over numerous years, rather than just being a quick and easy solution that can be rolled out in a number of months. The issue is that with Covid-19, even the most stringent and forceful lockdowns have not really been successful in preventing the spread of the disease. This has meant that the creation of vaccines is at the forefront of the fight against Covid-19. Therefore, vaccine accelerators, by which vaccines get produced in unprecedented times have started to take place. The issue, though, is that side effects can take years to actually properly appear. The question is therefore how to weigh up the potential damage of a vaccine having unintended consequences with the harm and suffering that permeates throughout the entire world before a vaccine is able to be rolled out.
Vaccines are created by either trying to stimulate the body’s immune response to mirror that which would come about should one actually have the illness, without actually making them have any sort of virus that could cause harm to them. Vaccines are effectively just the virus which is altered such that it will not be harmful whatsoever. This is the process for creating vaccines and has worked for many viruses in the past. Now though, due to the huge advances in science in recent history, the creation of vaccine has been even more automated such that the first vaccines were created only days after the genome was mapped in China, which even in itself was mapped much faster than had been done previously. This has allowed a faster than ever production of vaccines, but even then, the lowest estimates expect that vaccines will be here with us only in another year from when the genome was mapped in early January. Although testing has already begun, vaccines generally require 3 stages of testing, with increasing numbers of people, in order to properly access how the vaccine will affect the body and to gage dosage. This means that even in an ideal world, only in a further 10 months from now will vaccines actually come around to stay and join the fight against Covid-19.
In addition, vaccine production, in order to be safe, takes numerous sets of trials to create. It is not simply possible to just have an experimental vaccine and then just start mass-producing it, but rather have to go through all the loops, and if it is not certain that a vaccine will be successful, then it cannot just start being spread to millions of people around the world. Notably, the first SARS vaccines when tested in ferrets actually increased the virulence of the disease, as it inflamed their livers when they got infected. This sort of enhancement can actually make diseases even worse, and therefore it is vital that a vaccine is screened to be safe through these trials first, making the process something that is not coming as our saviour any time soon.
But even if this vaccine works, two further issues still remain. Due to how Covid-19 is a novel illness, it is still somewhat unclear whether humans will develop immunity to Covid-19 purely by being exposed to it and how long this immunity will last if they do develop some form of immunity.
First, the issue with immunity is that in many cases these viruses come and go, without actually conferring immunity onto people who get the virus. Most research seems to suggest that at the very least some form of immunity will be conferred onto everyone who gets it, but there remains a lack of studies and evidence that suggests that truly Covid-19 will confer immunity onto everyone who gets it. A study on rhesus macaques in China suggested that Covid-19 would provide some sort of future immunity, and therefore a vaccine would provide similar immunity, as 4 weeks after being diagnosed and having recovered from mild Covid-19 cases, the macaques were again exposed to the virus but did not catch it despite significant exposure.
But, even if immunity does develop, the corollary question is how long it will remain there for. For example, in particular with coronaviruses, the two coronaviruses which are present as types of seasonal flu both do not confer long term immunity. This suggests that coronaviruses in general do not confer long-term immunity, and there seems to have been a number of cases in China where someone has got coronavirus, then recovered and then got it again, although it is very plausible that this is simply the Covid-19 not being cured in the first place and just suppressed. A similar situation took place in Japan, by which a Japanese bus driver managed to get Covid-19 twice in the same week. Similarly, MERS, a close relative of Covid-19, was seen to have very high drop-off rates in antibody counts once someone was cured with the virus, suggesting that perhaps getting Covid-19 is a less watertight way of being safe from getting it in the future than some might have hoped. On a brighter note, SARS antibodies in most studies still seem to be present in the body 15 years after infection, although whether this would be sufficient to prevent infection is yet to be seen.
Therefore, stick to the social distancing and containment. With any luck, Covid-19 will be able to be eradicated into obscurity after 2 or 3 months, as vaccines are a long way off, and even if they do ever come around, it’s not even certain that they will be successful. But, at least, if the storm is never calmed, given the sheer quantity of vaccines hopefully one of them will work.