Enlarge /. British Prime Minister Boris Johnson poses for a photo with a vial of the vaccine candidate COVID-19 from the University of AstraZeneca / Oxford.
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This week the UK released more data on the newly developed strain of SARS-CoV-2, which provides further evidence that it is spreading more easily than previously circulating strains of the virus. Despite efforts to confine it to the UK, most public health experts expected it was already too late – a fear confirmed by the discovery of cases in Colorado. There is some good news, however, as the UK data suggests that the new strain does not appear to be any more dangerous to humans after infection.
In another piece of good news, UK health officials approved the use of a different vaccine resulting from a collaboration between Oxford University and pharmaceutical company AstraZeneca. While the vaccine doesn't appear to be as effective as the other two, which are already in widespread use, the addition of another supplier ensures the UK has enough vaccine for its entire population early next year.
New, but definitely not improved
As the coronavirus accumulates mutations over time, many different SARS-CoV-2 strains are now circulating. The one now of concern first caught the attention of UK medical authorities because it sparked a wave of new infections at a time when targeted lockdown measures were reducing the number of other strains. In mid-December the strain had a name (B.1.1.7), was widespread in Great Britain and had already been discovered elsewhere in Europe. But almost everything else about the strain was an open question, including whether it was actually more contagious or just circulated in groups that were more likely to pass it on to others.
In a new report, Public Health England is attempting to answer some of these questions while creating confusion by giving the strain a completely different name (in its report, VOC 202012/01 is used for "variant of concern"). We will continue to refer to it as B.1.1.7.
While the UK originally identified it by sequencing viral genomes, B.1.1.7 has a deletion that removes part of one of the three viral RNA sequences recognized by a commercial test used in the UK. This has allowed health officials to track it in any region where the test is widely used (around 30-35% of tests used can detect it). However, there are other strains that lack this sequence, so the numbers generated in this report should be viewed as an upper limit to the spread of B.1.1.7.
In view of this limitation, the increase in prevalence demonstrated in B.1.1.7 is astonishing. In mid-October it was only about three percent of the viruses examined in Great Britain. By mid-November that number had risen to 88 percent, a month later to 98 percent. There were no apparent significant differences in infection – all ages, genders, and ethnic groups showed similar proportions of the new strain compared to total infections.
The UK national health system made it possible for researchers to track the results of those infected with B.1.1.7. Public Health England researchers identified 2,700 of them and adjusted their demographics to match a group of 1,770 infected with other SARS-CoV-2 strains. There were no significant differences in the percentage who were hospitalized or died because of his infections. So it seems possible that the only difference between B.1.1.7 and other strains is increased infectivity.
It is everywhere
The UK contact tracing features paid off when it came to estimating what is known as the attack rate, or the percentage of those exposed to a viral host that actually becomes infected with the virus. In the UK, all other virus strains had an attack rate of just under 10 percent. The attack rate of B.1.1.7 was over 15 percent. This is definitely in line with the idea that this tribe can spread more easily among humans than those previously circulating.
While a number of countries restricted travel to the UK based on previous reports on B.1.1.7, most health authorities said such steps were too late – it was so common and widespread in the UK that there was clearly an opportunity this had to spread further before restrictions were introduced. It was no surprise when the virus was found in a number of other countries as well.
The US viral surveillance system is not as thorough as the UK, so the variant was expected to be in circulation here as well. That was confirmed yesterday with the discovery of a case in Colorado, followed by the announcement of another suspected case there today. These two cases worked in the same facility and the person who definitely has B.1.1.7 has not traveled outside of the US in the past. Taken together, this suggests that B.1.1.7 is already floating around in communities within the US, which means it will be very difficult to contain.
If the virus's higher rate of attack occurs here too, it could greatly increase the challenge of taking care of all those infected. Given that some areas of the US are already out of hospital capacity, this would make the New Year even grimmer than it was anticipated.
More help could be on the way for the UK as the country's drug and health products regulator has approved another vaccine, resulting from a collaboration between Oxford University and pharmaceutical giant AstraZeneca. The vaccine is based on a harmless chimpanzee virus belonging to a family of viruses that cause cold symptoms in humans. It is designed to produce the coronavirus spike protein in all infected cells. The virus is incredibly easy to make, which makes it cheaper. It can be stored in standard freezers, which makes it easy to spread.
The downside is that it doesn't appear to be as effective as Moderna and Pfizer / BioNTech's RNA-based vaccines. Full-dose studies showed it was only 62 percent effective compared to over 90 percent for RNA-based vaccines. A subgroup using a different protocol had seen 90 percent protection, but there were questions about whether that group was representative. Still, the UK has made it the centerpiece of its vaccination policy, ordering 50 million doses – enough to cover most of its population – and expecting them to be given as early as March.
(There may be a bit of nationalism at play, with Matt Hancock, UK Secretary of State for Health and Welfare, calling Oxford's role a "UK success story." In contrast, Oxford's Andrew Pollard, who ran the clinical trials, called it "an endorsement." the enormous efforts of a dedicated international research team and our dedicated study participants. ")
According to the New York Times, the UK will also be taking an unusual approach to getting vaccinations. Like others, the Oxford / AstraZenica vaccine requires two doses. But rather than delivering these to people on a schedule, the UK will focus on getting as many people as possible realistically on their first dose in hopes of partial protection before making sure someone gets their second.
Even if the vaccine is only partially effective, it can help lower the rate of virus reproduction to the point that additional controls such as mask use and social distancing lower the virus reproduction number enough that the pandemic fades. The UK's experience in this regard will be crucial as the price and ease of transportation make it likely that the Oxford / AstraZenica vaccine will be widely available in developing countries.