Nobbling Viral Variants?

Just in case, some of my overseas readers are unfamiliar with the term, I had better explain what 'nobbling' is. Nobbling is a generally illegal attempt (often in horse racing) to improve the chances of your preferred candidate winning the race, by suppressing the performances of rivals (e.g.'doping'). I was reminded of this possibility, by the debate about the relative ineffectiveness of the Oxford/AstraZeneca Covid-19 vaccine against the South African (SA) variant of the virus (https://www.theguardian.com/world/2021/feb/08/more-than-90-percent-over-75s-uk-first-covid-jab). The Oxford/AstraZeneca Covid-19 vaccine does not appear to prevent mild or moderate infections with the SA variant. This conclusion is based on a small study carried out in South Africa (although it seems a real enough finding).There currently seem to be only small numbers of the SA variant in the UK. The SA variant is said not to have a distinct transmission advantage over the currently-dominant 'Kent' variant. Consequently, Professor Jonathan Van-Tam (Deputy Chief Medical Officer for England) claimed "Because of that, there is no reason to think the South African variant will catch up or overtake our current virus in the next few months". He is probably absolutely right but the key phrase is 'in the next few months'. If vaccination makes transmission difficult (by removing susceptible hosts) for the 'Kent' variant, this 'nobbling' might well offer increased opportunities for the SA variety. The process seems analogous to the development of antibiotic-resistant strains of bacteria. They thrive when their competitors are killed by the antibiotic. Uptake of vaccine in the UK is currently very good and people should certainly not be discouraged from being vaccinated. Any protection is better than no protection. Reducing life-threatening infections will also reduce the current pressure on hospitals. It does seem likely, however, that booster doses will be needed (e.g. a 3rd dose for people given the Oxford/AstraZeneca vaccine?), protect us against new and current variants of Sars-CoV-2. This virus is going to carry on mutating and vaccines are going to require periodic tweaking.