Brisbane is going into lockdown after just one case of a new British strain of the virus was detected there.
What do we know about this strain so far?
Professor Trevor Drew, Director of CSIRO's Australian Centre for Disease Preparedness
"The UK variant is one of many that have occurred in different parts of the world.Emergent viruses do change over time,so in that sense this is entirely to be expected. These changes are driven by several factors as they adapt to their new host,and due to other pressures, such as increasing levels of immunity in the populations in which they circulate.
"There are actually several mutations in different viral proteins of the UK variant, compared to the original SARS CoV-2,and scientists are still confirming the effects of these mutations.
"One potential effect is to make the virus more infectious. In theory, this might be caused by increasing the efficiency of the virus to bind – and the mutations in the spike protein might contribute to this. But other mutations in different parts of the virus might also contribute to increased infectivity. This might involve virus entry into the cell, the efficiency of replication, or other ways in which the virus might avoid other arms of the immune response, resulting in increased excretion of live virus, over a longer period.
"It is interesting to note that some of the mutations in the spike protein of the UK strain are also seen in a new strain which has emerged in South Africa – but there are also other, significant differences between the two viruses, which indicates they are not closely related. This indicates that these particular mutations are likely giving the virus some sort of advantage over conventional strains, which is resulting in them becoming more dominant."
Does it cause more transmission and/or severe disease?
Professor S.S. Vasan, CSIRO's COVID-19 Project Leader & Senior Principal Research Consultant
"It is natural for SARS-CoV-2 to mutate, and we expect more mutations as the rollout of vaccines will put the virus under selection pressure. Therefore, since March 2020, we have been tracking variants of this virus across the world. In recent months key variants have been identified in Denmark, Malaysia, South Africa and the UK, of which the last two are currently of concern.
"From the data I have seen, the UK variant is more transmissible but does not appear to increase disease severity or mortality. There is anecdotal evidence from South Africa that its variant may result in more cases of severe disease in younger patients, but we have to wait for more peer-reviewed data on this.
"It's only a matter of time until the two new variants originating from the UK and South Africa find their way to different parts of the world, so it will be prudent to sequence the virus genome from all imported cases and check for the variant(s). The UK and South African variants share the N501Y mutation which enhances receptor binding affinity, and the well-known D614G mutation which is now present in over 90% of the isolates of this virus."
Will the Pfizer BioNTech and Oxford-AstraZeneca vaccines work against this new strain?
Professor S.S. Vasan, CSIRO's COVID-19 Project Leader & Senior Principal Research Consultant
"Our research last year showed the D614G mutation (otherwise known as the 'G-strain'), another more transmissible form of the virus, should still be vulnerable to vaccines that targeted the spike protein.
"We used experiments as well as biomolecular modelling to draw our conclusions.Based on that, I expect the new variants from UK and South Africa are also unlikely to affect vaccine efficacy,although it will take time to get this experimentally confirmed.
"In general,vaccines induce an immune response to multiple sites on the spike protein, so alterations to one or two sites may not be so important.Nevertheless, we continue to monitor changes in this virus very carefully,so we are alert to any potential future impacts on vaccine efficacy."
How long until a vaccine becomes available in Australia?
Dr Rob Grenfell, CSIRO Health and Biosecurity Director
"On 7 January the Australian Government announced the rollout of a vaccine for COVID-19 will be brought forward to mid- to late-February, once approved by the Therapeutic Goods Administration.
"This is a great step towards controlling COVID-19 in Australia.
"The vaccine will be made available in a staged process in Australia, through targeted vaccination programs to the most vulnerable and at-risk people as determined by an expert committee.If the first vaccine approved is the Pfizer-BioNTech vaccine, this staged process will be necessary as the first supply will be 10 million doses (enough for five million people),and considering the logistical challenges of distributing this vaccine at -70 degrees Celsius.
"For the rest of us, with more vaccines eventually available, we can hope to see immunisations for the general public as the year progresses."
How is this all being done so fast, and is it safe?
Dr Rob Grenfell, CSIRO Health and Biosecurity Director
"It's important to note that while the logistics are being sped up, safety is remaining everyone's top priority. We can be reassured by the approach that Australia's independent Therapeutic Goods Administration (TGA) is taking, as one of the most stringent regulatory agencies in the world.
"This outcome has only been possible because the world's scientists, organisations and funding have all been laser-focussed on solving the one problem.It's a significant milestone in scientific history.
"Which ever vaccines are approved by the TGA will have passed stringent Phase III human clinical trials, as is standard for all vaccines approved for other diseases in Australia.
"But the process doesn't end there. As vaccines are rolled out here and overseas, any side effects will be closely monitored.We've already had an example of this, with new advice issued for the Pfizer vaccine in the UK late last year for people with a history of severe allergic reactions.
"It's also reassuring to know that a few million people have already received the Pfizer vaccine overseas without major safety issues.Health authorities will continue to monitor."
Once we get a vaccine, what will happen in Australia?
Professor Trevor Drew, Director of CSIRO's Australian Centre for Disease Preparedness
"A vaccine will reduce the number of people getting severely ill.However, vaccines are unlikely to completely eliminate virus circulation.
"This is because there are still likely to be people who are not vaccinated,so virus may still have an opportunity to transmit – especially in densely populated areas,or in cohorts which have lower vaccine coverage.
"We also know that current vaccines are unlikely to induce'"sterile immunity',meaning that there may still be a mild infection and re-excretion of virus in a vaccinated person. This means there is a possibility that they can transmit the disease, even if they seem healthy.
"We also need to keep in mind that immunity will create another selective driver for mutation of the virus. So it's important to ensure that, once vaccines are deployed, coverage is maximised and full immunity is achieved as quickly as possible, also by giving the two doses within the timeframe recommended by the manufacturer.
"For these reasons,it will not be possible for life to go back to normal immediately. It is important that we continue to follow the established protocols to avoid transmission, even once a vaccine is deployed in Australia. We will need time to be able to be sure the vaccine is effective in stopping the virus from circulating, as well as preventing disease."
How do scientists refer to specific mutations?
Professor Trevor Drew, Director of CSIRO's Australian Centre for Disease Preparedness
"The genomic material of the virus consists of a chain of molecules, a bit like a string of beads. These molecules, called nucleotides, are arranged in a specific order and form the "genetic code" of the virus, with every three nucleotides encoding an amino acid – the building blocks of proteins–so their order is really important. If a nucleotide changes, that can change an amino acid, which can then result in a change in the structure of the protein.
"Every virus has a designated "Reference Strain" which is used when referring to any changes. So, a mutation which is described as "N509Y" means that the amino acid N at position 509 in the reference strain is changed to a Y in the mutant.All our proteins are comprised of combinations of up to 20different amino acids, each designated by a different letter, so the possible combinations are huge. But for a mutation to be tolerated, it must at least not affect the function of the protein. And for it to persist, it needs to provide some advantage.
"Sometimes deletions occur in the genome, which results in some amino acids in the protein being completely deleted. In such a case we simply refer to it as, for example, an H69/V70 deletion or ΔH69/V70, which means that amino acids H and V at positions 69 and 70 are missing in the mutant."
