Little conviction about UK COVID variants, except for continuous spread

According to scientists, a new highly mutated SARS-CoV-2 strain that is prevalent in the UK has already spread COVID-19 worldwide, with the recent surge that hit hospitals and the currently approved vaccine. It fuels concerns about whether it can be stopped.

The fact that the mutant developed 23 mutations in a few months, according to top US experts, is also a reason for concern.

According to the World Health Organization on December 21, this variant, called B.1.1.7, caused more than 50% of COVID-19 cases in the United Kingdom from October 5 to December 13, mainly 60. It occurred in people under the age of. Report.. Virus replication count (R₀), The number of people that can be infected by one infected person (1.1 to 1.5) suggests that it is much more contagious than previous “wild-type” strains, Brief said.

On an ongoing international trip between the United Kingdom and the United States, less than half of the US viral genome has been sequenced, so the mutant strain may already be circulating undetected in the United States, but its presence Has not been confirmed. Centers for Disease Control and Prevention (CDC) simple yesterday.

Stanley Pearlman, MD, a professor of microbiology and immunology and pediatric infectious diseases at the University of Iowa in Iowa City, suspects it is already in the United States. “If not, I would have been surprised,” he said.

Many countries are closed to British travelers, but if the rapid spread of the new SARS-CoV-2 strain is caused by its mutations rather than just epidemiological factors, it will inevitably penetrate the border. Will, said Dr. Christian Andersen at the Department of Immunology and Microbiology at the Scripps Research Institute in La Jolla, California. “We shouldn’t think about it [a border closure] I’m going to prevent you from coming here, “he said. Come here and start spreading to the locals. “

Is the new vaccine effective against it?

The new strain prompted questions about whether the current COVID-19 vaccine can dodge it. But when manufacturers are in a hurry to test vaccines, Dr. Jesse Bloom, an associate professor at the Fred Hutchinson Cancer Research Center in Seattle, MPhil said, is likely to be effective against new variants. I did.

Human coronavirus can evolve gradually to escape antibody-based immunity, and British variants may mean the initiation of this process, but “because this evolution occurs over the years, vaccines Should not immediately raise concerns about the effectiveness of the virus, “he said.

Bloom said scientists need to monitor SARS-CoV-2 mutations to see if they are gradually avoiding antibody immunity. At that point, you should be able to easily update your current vaccine. This is especially true for mRNA-based formulations such as the Pfizer-BioNTech and Moderna vaccines, where spike protein sequence changes are relatively easy. These are the only two COVID vaccines approved by the Food and Drug Administration.

“But based on the time course of viral antigen evolution … this will only be a problem in a time frame that spans years. It gives us enough time to respond as scientists,” he says. It was. “You don’t have to worry that even the slightest mutations like the British strain will completely invalidate the vaccine.”

However, despite the potential efficacy of the vaccine against new strains, Andersen said, in addition to testing the vaccine, manufacturers need to be prepared to revise, manufacture, and distribute updated versions. Said. “You shouldn’t wait to prove it before you take action,” he said. “I can’t be wrong about this.”

23 mutations in a few months

According to the CDC overview, scientists are wondering if mutations are responsible for the rapid spread (rather than human behavior), affect the severity of clinical illness, avoid diagnostic tests, or innate immunity. Or trying to determine if it affects vaccine-induced immunity. Less likely to cause reinfection or less susceptible to treatments such as monoclonal antibodies.

However, the very short time it took to develop more than 20 mutations from rare strains to UK compared to one or two additions or deletions expected to be developed in that time frame. With the rapid change to common stocks, there are concerns, Perlman said. “I think what this teaches us is that we have to be careful,” he said. “Such mutations do not happen easily.”

According to the CDC overview, a notable mutation in this variant is N501Y in the viral peplomer, which is thought to enhance binding to the human angiotensin converting enzyme 2 receptor. Most of the individual mutations have been seen before, Perlman said, “but maybe they will do a little better as a team.”

Andersen called the highly mutated variants “a whole new region.” This is because it could not evolve so quickly according to the expected evolutionary process. “Another process created this,” he said.

According to Andersen, the process is a chronic infection, immunodeficiency, treated with restorative plasma containing SARS-CoV-2 and perhaps the antiviral drug remdesivir, an environment that can promote mutations. Or it is likely to have occurred in one immunosuppressed COVID-19 patient.

Detection and mitigation measures

On December 14, the United Kingdom detected the SARS-CoV-2 variant through the COVID-19 Genomics UK (COG-UK) consortium, a robust real-time SARS-CoV-2 genome monitoring system. December 20 Risk assessmentAfter the European Center for Disease Prevention and Control noticed that the 14-day case notification rate in southeastern England increased significantly from 100 per 100,000 in early October to 400 per 100,000 in December. He said he had begun strengthening epidemiological and virological investigations. ..

Sequencing of virus samples in the most affected region, Kent, occurred at the same time as the emergence of a November subspecies in which the country was partially blocked during Europe’s second surge. I showed that. However, the geographical origin of the British variants is unknown, Perlman said. “For amplification It got a lot of attention in London, but that doesn’t mean it started in London. “

This new strain has recently been identified in other European countries such as the Netherlands, Italy, Iceland and Denmark, as well as Australia. Another highly mutated, rapidly spreading SARS-CoV-2 mutant, unrelated to the UK mutant, but particularly with the same N501Y mutation, came to light in South Africa shortly after the UK mutant was identified. It came out. The strain was found in up to 90% of patient samples genetically analyzed since mid-November. New York Times Reported on December 20th.

Last week, Britain implemented the strictest blockade in the country since March and closed its borders. As a result, transportation was significantly interrupted. Following the proceedings, other countries in Europe, Latin America, the Middle East, and North America (Canada, but not the United States) closed their borders with British travelers in an attempt to stop the mutated coronavirus.

Urgent need for better US surveillance

Andersen said the UK’s detection of viral variants through a genome surveillance system indicates that a similar federal program is needed in the United States. “It shows the need to have incredible power and a really powerful surveillance system, especially when the United States deploys vaccines,” he said. “Importantly, such programs will also be possible [the United States] To detect what the UK has done with these mutations. “

According to the CDC, small initiatives such as CDC’s SARS-CoV-2 Sequencing for Public Health Emergency Response, Epidemiology, and Surveillance (SPHERES) are occurring nationwide. simple.. The program started in November but will not be fully functional until January.

Perlman agreed that close scrutiny is important as SARS-CoV-2 and its variants continue to change over time. “I don’t know if that will be a big deal,” he said. “The point is that you need to be vigilant, but nothing scares people.”