New virus variant found in Colorado as UK pushes to limit it

This week, the UK released more data on the newly evolved strain of SARS-CoV-2, providing further evidence that it spreads more easily than previously circulating strains of the virus. Despite efforts to limit it in the UK, most public health experts believed it was already too late – a fear confirmed by the discovery of cases in Colorado. There is good news, however, as data from the UK indicates that the new strain does not appear to be more dangerous to people once infected.

In other good news, the health authorities in the United Kingdom have approved the use of another vaccine, this one resulting from a collaboration between the University of Oxford and the pharmaceutical company AstraZeneca. While the vaccine does not appear to be as effective as the other two already widely used, the addition of another supplier ensures that the UK should now have enough vaccines for its entire population by early next year.

New, but definitely not improved

Because the coronavirus accumulates mutations over time, there are now many distinct strains of SARS-CoV-2 in circulation. The one currently causing concern first caught the attention of UK medical authorities as it sparked a wave of new infections at a time when targeted lockdown policies were reducing levels of other strains. By mid-December, the strain had a name (B.1.1.7), was circulating widely in the UK and had already been spotted elsewhere in Europe. But almost everything else about the strain was an open question, including whether it was actually more contagious, or if it just ended up circulating among groups that were more likely to pass it on to others.

In a new report, Public Health England attempts to answer some of these questions, while adding confusion by calling the strain a completely different name (its report uses VOC 202012/01, for “variant of concern”). We will continue to call it B.1.1.7.

While the UK originally identified it by sequencing viral genomes, B.1.1.7 has a deletion which removes part of one of three viral RNA sequences recognized by a commercial test used in United Kingdom. This has allowed health authorities to track it in all areas where the test is widely used (around 30-35% of tests used can recognize it). However, there are other strains which also do not have this sequence, so the numbers generated in this report should be considered as an upper limit for the spread of B.1.1.7.

Given this caveat, the increase in prevalence demonstrated by B.1.1.7 is startling. As late as mid-October, it made up only about 3% of viruses sampled in the UK. By mid-November, that number had risen to 88 percent, and it was 98 percent a month later. There were no apparent significant differences in who was infected – all ages, genders, and ethnicities had similar proportions of the new strain to the total number of infections.

The UK’s National Health System has enabled researchers to track the outcomes of people infected with B.1.1.7. Researchers at Public Health England identified 2,700 and compared their demographics to a group of 1,770 infected with other strains of SARS-CoV-2. There was no significant difference in terms of the percentage of people who ended up being hospitalized or died from their infections. Thus, it seems possible that the only difference between B.1.1.7 and other strains is high infectivity.

It’s everywhere

The UK’s contact tracing capabilities have paid off when it comes to estimating what’s called the attack rate, or the percentage of people exposed to a viral host who end up contracting the virus. . In the UK, all other strains of the virus had an attack rate of just under 10%. The attack rate of B.1.1.7 was greater than 15%. This is certainly consistent with the idea that this strain is able to spread more easily among humans than those that have circulated before.

While a number of countries restricted travel with the UK in response to earlier reports on B.1.1.7, most health authorities said these movements were too late – it was so common and widely publicized in the UK that it had clearly spread further before the restrictions were put in place. It was no surprise when the virus was also detected in a number of other countries.

The virus surveillance system in the United States is not as comprehensive as that in the United Kingdom, so the variant should already be circulating here as well. This was confirmed yesterday, with the discovery of a case in Colorado, followed by the announcement of another suspected case there today. Both of these cases worked at the same facility, and the person with definitive B.1.1.7 has no recent travel history outside of the United States. Together, this suggests that B.1.1.7 is already circulating within communities in the United States, which means that it will be very difficult to contain it.

If the highest attack rate of the virus occurs here as well, it could significantly increase the challenge of caring for everyone who is infected. Given that a number of regions in the United States are already out of hospital capacity, that would make the new year even darker than it already was.

Another vaccine

For the UK, further help may be on the way as the country’s Medicines and Health Products Regulatory Agency has approved another vaccine, this one from a collaboration between the University of Oxford and pharmaceutical giant AstraZeneca. The vaccine is based on a harmless chimpanzee virus from a family of viruses that cause cold-like symptoms in humans. It was designed to produce the coronavirus spike protein in all the cells that it infects. Producing the virus is incredibly easy, making it cheaper, and it can be stored in standard freezers, making it easy to distribute.

The downside is that it doesn’t appear to be as effective as the RNA-based vaccines made by Moderna and Pfizer / BioNTech. Full-dose trials indicated that it was only 62% effective, compared to over 90% for RNA-based vaccines. A subgroup that used a different protocol saw 90% protection, but there were questions as to whether this group was representative. Yet the UK has made it the centerpiece of its vaccination policy, and has ordered 50 million doses – enough to cover most of its population – and expects to receive them as early as March.

(There may be a bit of nationalism at play, with Matt Hancock, the UK Secretary of State for Health and Welfare, referring to Oxford’s role as calling it a ‘British success story.’ In contrast, Andrew Pollard of Oxford, who led the clinical trials, called “an endorsement of the enormous effort of a dedicated international team of researchers and our dedicated trial participants.”)

According to the New York Times, the UK will also take an unusual approach to administering the vaccines. Like others, the Oxford / AstraZenica vaccine requires two doses. But, instead of delivering them to people on a schedule, the UK will focus on getting the first dose to as many people as possible, hoping for partial protection, before making sure. that whoever receives the second.

Even though the vaccine is only partially effective, it can help lower the rate of viral reproduction to the point where additional controls, such as the use of masks and social distancing, reduce the number of viral reproductions enough to make it possible. disappear the pandemic. The UK experience in this regard will be crucial, as the price and ease of transport make it likely that the Oxford / AstraZenica vaccine will be widely used in developing countries.