The UK has become the first country to approve a dual vaccine which tackles both the original Covid virus and the newer Omicron variant.
The upgraded vaccine should be available as an autumn booster and give better protection against variants.
Moderna said it could supply doses in the next few weeks, but exactly who will get them has yet to be announced.
All over-50s and people in high-risk groups will be offered some form of booster from next month.
The original vaccines used in the pandemic were designed to train the body to fight the first form of the virus that emerged in Wuhan, in China, at the end of 2019.
The Covid virus has since mutated substantially, with a stream of new variants emerging that can dodge some of our immune defences. They have caused large surges in cases around the world.
'Sharpened tool'
Moderna's vaccine targets both the original strain and the first Omicron variant (BA.1), which emerged last winter. It is known as a bivalent vaccine as it takes aim at two forms of Covid.
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[ Source: https://www.bbc.co.uk/news/health-62548336 ]
Personally I'm quite disappointed to see the second protein coding sequence based on BA.1 (spike I assume). I know that there is way more to immunity than neutralising antibodies but it is neutralising antibody titres (henceforth "NAT") that most reports seem to focus on and reading between the lines it looks as if the efficacy measure used for this approval was NAT results; I can't imagine that there was time and/or the ability to recruit sufficient Omicron-naïve volunteers to run a meaningful trial based on clinical outcomes. My problem is that from reports I have read looking at in vitro NAT experiments BA.1 does indeed show a lot of immune escape vs Delta (i.e. how good pre-BA.1 antibodies are at forming a neutralising binding with BA.1 spike) but there seems to be an even bigger step-change in reduction when going from BA.1 to BA.4 or BA.5 so as a layperson I do feel somewhat disappointed that it is not BA.4 or ideally BA.5 that was targeted. Just not enough time I suppose.
I confess that I will want to do a lot more research and try and find some more in-depth expert discussion about the potential risk-reward of the various booster options for my particular case (healthy male 63 year old) before I sign up for a booster this winter. I do note in the article that it is not clear yet who in the UK will get this bivalent vaccine and if it is in limited supply I can imagine it only going to the most vulnerable with the rest of the over-50s only being offered a booster with one of the previous set of vaccines, and frankly I am even more sceptical of that option but as always am open to changing my mind if solid scientific consensus does seem to be out there that the risk-reward proposition makes sense for my situation.
- Julian
