Vaccines can have amazing efficacy in clinical trials but things may be different in the real world when you are dealing with different populations and exposure to different virus strains. That is a normal part of vaccine development and global rollout, and we must manage expectations around this. Nathan Bartlett describes why South Africa has paused using AstraZeneca COVID-19 vaccine
South Africa will pause its rollout of the AstraZeneca COVID-19 vaccine after a small study suggested it offers minimal protection against mild and moderate infection from the South African coronavirus strain known as B.1.351.
The South African health minister said the government was waiting for scientific advice on next steps.
A media release issued overnight by the University of Oxford said a study of about 2,000 volunteers with an average age of 31 found a two-dose regimen of the AstraZeneca vaccine (officially known as ChAdOx1 nCov-19):
provides minimal protection against mild-moderate COVID-19 infection from the B.1.351 coronavirus variant first identified in South Africa. Efficacy against severe COVID-19 infection from this variant was not assessed.
The analysis is yet to be peer reviewed or published.
The AstraZeneca vaccine, sometimes also called “the Oxford vaccine”, is a core plank in Australia’s coronavirus vaccine plan, with the Australian government securing 53.8 million doses. It’s worth remembering, though, that it’s just one of the vaccines that will be made available in Australia — and that vaccines are just one of a range of responses we will need to get the pandemic under control.
So what’s all this mean for you? There’s no doubt this news is disappointing — but it’s also no great surprise given how quickly this virus mutates. And it doesn’t yet mean Australia should abandon its plan to rollout the AstraZeneca vaccine.
The sobering reality is setbacks such as these are to be expected in vaccine development, especially when dealing with an agile, fast-mutating virus such as this coronavirus.
Still better for Australia to have AstraZeneca than not
It’s reasonable for the South African government to pause while it reflects on what these new data mean.
For Australia, it’s too early to bin the AstraZeneca vaccine as part of our rollout, especially as the South African variant is not yet prevalent here. If we did that every time we got new data, we would never get any vaccines out. I think, at this point, it is still better to have the AstraZeneca vaccine in Australia than to not have it.
Based on Australia’s current circumstances, I think it’s reasonable to say we just need anything that will help reduce the risk of severe disease. That will help ease the burden on health-care systems.
We will get better vaccines coming out all the time. It’s an iterative process.
Encouragingly, Oxford said in its press release that:
Work is already underway at the University of Oxford and in conjunction with partners to produce a second generation of the vaccine which has been adapted to target variants of the coronavirus with mutations similar to B.1.351, if it should prove necessary to do so.
Such an agile virus demands a range of responses
These new developments highlight how quickly this incredibly agile coronavirus adapts and changes. While the level of infection remains so high, we must get used to the idea that new strains will be appearing all the time.
Vaccines are best suited to stationary targets and currently, SARS-CoV-2 is anything but — with so much human infection occurring, the virus has huge opportunity to mutate and generate variants.
Having said that, the newest vaccine technologies such as mRNA vaccines (including what’s commonly known as the Pfizer vaccine) can rapidly update and reformulate to keep up with mutant viruses.
Of course, it still takes some time to manufacture and distribute new vaccines so there will inevitably be a lag of months between identifying a new virus variant and making and distributing an updated vaccine.
A month is a long time in a pandemic. That underscores how critical treatments addressing these gaps are going to be if we are to have any chance of bringing this pandemic to an end within the next couple of years. Those responses will likely include antivirals that reduce duration of infection and other treatments that provide rapid, broad spectrum protection against viruses by directly boosting innate immunity in the airways.
Vaccines can have amazing efficacy in clinical trials but things may be different in the real world when you are dealing with different populations and exposure to different virus strains. That is a normal part of vaccine development and global rollout, and we must manage expectations around this.
We always knew the first-generation vaccines would be far from perfect, and certainly not a magic bullet. As scientists have said all along, this is a long game with incremental gains. And with so much research focused on beating this pandemic, there is huge reason for optimism.
We don’t want people to be discouraged from getting vaccines. Based on current circumstances and the fact the South African variant is not yet prevalent in Australia, the AstraZeneca vaccine will be one of a suite of responses that will help bring a reduction in serious disease in the first place — and ultimately prevent transmission as vaccines become more effective and supported by other treatments.
Just like you get a new flu shot every year, so it may be in the future you get a new coronavirus jab as better and more targeted vaccines become available.
New treatments will become available to support better and better vaccines, which will slowly but surely bring an end to this pandemic.
Nathan Bartlett is Associate Professor, School of Biomedical Sciences and Pharmacy, University of Newcastle
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