As the pandemic rumbles begrudgingly on, epidemics themselves are fluctuating depending on weather, behaviour, policy and other socio-cultural influences. In the northern hemisphere, the inevitable darkness of winter is creeping in, forcing many of us inside and back into the territory of SARS-CoV-2 which thrives on proximity and concentration of humans. Whilst a vast majority of the western world is accepting vaccines and booster doses, the category of ‘vaccine hesitant’ might be bolstering now in the wake of yet another Covid variant which is set to partially evade immunity. The Omicron variant has recently emerged in Gauteng, South Africa, and is the most mutated variant to date, with particular changes in spike protein and receptor binding domains. These changes have been speculated as being ‘dangerous’ and potentially a gain of function by the variant to evade natural immunity and antibody reliability generated by prior infection or vaccination.
Whilst the evidence is preliminary in the case of Omicron, it poses a difficult question. As many governments around the world touted, the vaccine is ‘the way out’ of the pandemic. In terms of hospitalisations and deaths, it is uncontroversial to state that the vaccines have absolutely outperformed all reasonable estimates of their efficiency in reducing virulency and mortality. Of the major approved vaccines, all produce immunity in such a way to mostly reduce coronavirus cases which would have been terminal to mild or moderate disease. Thus, we have around the world seen a general decrease in deaths in western countries to way above half of what we’ve seen in 2020. Despite government and WHO messaging, we still however see large spikes in cases and infections around the world, with the recent Delta variant bypassing substantially more of immunity in terms of infections, causing reinfection amongst vaccinated and unvaccinated individuals.
With the original wild-type virus, there would of expected to be a good deal of reduction in transmission, much like other vaccines we have available. With Delta, and even more so with Omicron (although the evidence is in its infancy), variants continue to evolve with a greater ability to cause reinfection and adapt to other mitigations we have put in place. What is the link to hesitancy, then? Many people in the UK came forward at the beginning of 2021 for their vaccination and received the Pfizer or Astra-Zeneca vaccine, with 46.4 million people in the UK having received a second dose by the time of writing. The category of individuals originally termed ‘vaccine hesitant’ are those who may be reluctant to step forward for a vaccine, are sceptical of their efficacy, or have other socio-cultural, religious or informed opinions on the novel mRNA vaccines. The vaccine hesitant category are those with access and convenience to receive a vaccination but do not come forward for their dose. Again, this may be for religious views, own opinions, or other moral and scientific reasons.
Presumably, the other percentage of the UK population therefore must have an exemption or have reasons to not come forward for their vaccine, something the government and WHO have deemed as causing further risk to vulnerable people, and the vaccinated. Of course, it is true that the only way for problematic variants such as Delta or even Omicron to arise is through mutation, and mutation is a product of multiple hosts and reproduction. Thus, a variant or coronavirus itself can be made extinct by preventing any transmissions, something which our current raft of vaccines unfortunately do not meet the criteria for. There may have been a larger group of vaccine hesitant people early on in their use because of the novelty of the science, uncertainty and other factors such as sensationalist stories, social media and ethics. In the wave of more and more variants which keep emerging and may begin to keep bypassing the vaccines we currently have in use (especially in the wake of the governments ramping up of the booster program) – is this group of ‘vaccine hesitant’ about to grow even bigger?
Booster doses of coronavirus vaccines have begun to be utilised throughout western Europe to combat a new expected surge in infections (which, unfortunately, have materialised), and to address the waning efficacy of vaccines to produce persistent immunity. Indeed, amongst all currently available vaccines, it is expected that the efficacy in preventing symptomatic infection over a period of 4-6 months may drop from 90% to 55-60%. In America, the Food and Drug Administration required vaccine efficacy to be above 50% after 6 months for authorisation, for example. Given the apparent need for ‘boosting’ (another dose of vaccine to achieve a further jump in immunity), there is inevitably a bigger degree of uncertainty of the general population around the need, or more, the ‘point’ of another dose.
With strains like Omicron arising and spreading around the world – even with the preliminary evidence suggesting immune escape – there is a reluctance in people to accept or see why another dose is better or will help the situation. If the booster doses received are based around the same wild type SARS-CoV-2 or even the alpha variant, people ask what efficacy this will have on a brand-new variant. The analogy of ‘dosing for something that is now in the past’ is apt, because it is known that booster doses give a good immune response to coronavirus – but does not assess whether this protects better for Delta, or even new and emergent variants. Indeed, the current vaccine technology is based around producing an immune response by getting cells to manufacture the coronavirus spike protein, allowing immune cells to neutralise this and generate antibodies to prevent infection. It is worth noting though, the spike protein that is generated by the mRNA is an ‘older’ version of the beta coronavirus. So, what does this mean going forward?
Some of the mutations in the newly emergent Omicron variant have worried scientists because there are multiple mutations to the spike protein and receptor binding domain. In simpler language, the ‘key’ that the new variant uses to get into your cells has fundamentally changed. Thus, when the ‘locks’ of your antibodies you may have generated from prior infection with Delta or through vaccination circulate in your blood, and find the SARS-CoV-2 virus – they may not work. The analogy of putting a key into a lock that has been changed is so apt, because it demonstrates the ability of this new variant to potentially bypass immunity – and once again, this may signal the beginning of a new, intensified pandemic. This could make certain individuals de-facto ‘partially unvaccinated’ – and if this is the case – the virus will find vulnerable individuals, those who are unvaccinated, or those unable to generate adequate immunity through other mechanisms to infect and cause disease.
The context to booster doses is that with future strains, we may be giving ‘old’ vaccines which are not updated to produce immunity relating to the most recent ‘key’ – the coronavirus spike protein’. If the locks change, you must call a locksmith – in this case, an updated vaccine. Moderna recently announced that should Omicron be a dangerous and problematic variant, a vaccine could be made to address it as early as March 2022. This bone breaking pace of development of a vaccine is only possible through these novel mRNA vaccines, which would have to go through further approval and safety study before being widely available. Whilst governments around the world are discussing the efficacy of our current vaccine to these new variants, we simply do not have the data. So, for the world, it is fingers crossed until we see if the vaccines work to an adequate extent. If they do not provide good immunity against Omicron or any other new variant, it would not be unreasonable to think that there is little point in receiving a 3rd dose of an ‘old’ vaccine next year.