1 00:00:00,299 --> 00:00:05,130 As the pandemic continues, variants have become the latest concern, 2 00:00:05,130 --> 00:00:07,823 with notable examples detected in South Africa, 3 00:00:07,823 --> 00:00:10,320 Brazil and the UK. 4 00:00:10,320 --> 00:00:12,943 But variants are complicated. 5 00:00:12,943 --> 00:00:15,735 Each one is made up of a collection of mutations, 6 00:00:15,735 --> 00:00:20,016 all of which have the potential to change the SARS-CoV-2 virus 7 00:00:20,016 --> 00:00:21,765 in unexpected ways. 8 00:00:22,379 --> 00:00:26,030 So what do scientists mean when they talk about variants? 9 00:00:26,030 --> 00:00:29,735 And what might this mean for the future of the pandemic? 10 00:00:30,854 --> 00:00:34,828 Viruses multiply by copying their genomes over and over. 11 00:00:34,828 --> 00:00:38,953 But like an old photocopier, these copies aren’t always perfect. 12 00:00:38,953 --> 00:00:42,286 Each of these imperfect copies is a variant. 13 00:00:43,120 --> 00:00:47,376 Normally the imperfections or mutations don’t change how the virus behaves, 14 00:00:47,376 --> 00:00:50,869 and they can often make it less successful than the original strain. 15 00:00:51,610 --> 00:00:54,541 But very rarely, mutations can change the virus 16 00:00:54,541 --> 00:00:56,431 in some important ways. 17 00:00:56,431 --> 00:00:58,565 It could become more infectious, 18 00:00:58,565 --> 00:01:01,742 or more able to avoid the immune system. 19 00:01:03,109 --> 00:01:06,000 The more a virus is allowed to replicate unchecked, 20 00:01:06,000 --> 00:01:09,987 the more chance it has to accumulate these rare beneficial mutations. 21 00:01:10,560 --> 00:01:12,065 That can occur when viruses 22 00:01:12,065 --> 00:01:14,948 are allowed to spread quickly through a population, 23 00:01:15,611 --> 00:01:18,554 or if they encounter a host that’s less able to fight them, 24 00:01:18,554 --> 00:01:22,287 such as people with compromised immune systems from medical treatment 25 00:01:22,287 --> 00:01:24,597 or those who are HIV+. 26 00:01:24,597 --> 00:01:28,657 If a particular set of mutations makes a variant more successful, 27 00:01:28,657 --> 00:01:31,096 it might become more prominent than others 28 00:01:31,096 --> 00:01:33,567 and that’s when it gets noticed. 29 00:01:33,567 --> 00:01:37,803 Epidemiologists may even decide to label it a variant of concern, 30 00:01:37,803 --> 00:01:41,595 like the examples identified in Brazil, South Africa and the UK. 31 00:01:42,680 --> 00:01:45,562 For months, scientists have been striving to work out 32 00:01:45,562 --> 00:01:49,770 what’s changed in these variants, and what those changes mean. 33 00:01:49,770 --> 00:01:52,983 Because a variant spreading doesn’t necessarily mean 34 00:01:52,983 --> 00:01:56,180 that it has an advantageous mutation. 35 00:01:56,180 --> 00:01:59,710 For example a small number of people could, by chance, 36 00:01:59,710 --> 00:02:01,870 move a variant from one region to another, 37 00:02:01,870 --> 00:02:05,590 like tourists travelling back from popular vacation spots. 38 00:02:06,310 --> 00:02:09,592 This could cause that variant to start spreading in a new location 39 00:02:09,592 --> 00:02:13,794 even though there may be no significant change to the biology of the virus. 40 00:02:13,794 --> 00:02:17,200 This is called the Founder Effect. 41 00:02:17,200 --> 00:02:19,504 Understanding why a variant has emerged 42 00:02:19,504 --> 00:02:21,828 requires a combination of studies. 43 00:02:21,828 --> 00:02:25,259 Epidemiology can help detect and trace new variants 44 00:02:25,259 --> 00:02:28,444 and flag new or worrying patterns of infection. 45 00:02:28,444 --> 00:02:31,606 Meanwhile lab studies can start to pinpoint 46 00:02:31,606 --> 00:02:35,506 how the mutations are changing the properties of the virus. 47 00:02:35,506 --> 00:02:39,063 And studies like these are starting to identify mutations 48 00:02:39,063 --> 00:02:42,043 that have given the virus an upper hand. 49 00:02:42,043 --> 00:02:46,940 Some variants are faster spreading, and there are hints that certain mutations 50 00:02:46,940 --> 00:02:51,620 could start to weaken or even evade natural and vaccine derived immunity. 51 00:02:52,510 --> 00:02:58,220 For example, the D614G mutation, known to virologists as Doug, spread widely 52 00:02:58,220 --> 00:03:02,290 in the early days of the pandemic and can be seen in almost all variants. 53 00:03:02,290 --> 00:03:04,662 It affects the spike protein 54 00:03:04,662 --> 00:03:07,820 that coronavirus particles use to penetrate cells. 55 00:03:07,820 --> 00:03:11,246 A mutation in the genome changes one amino acid for another, 56 00:03:11,246 --> 00:03:15,529 and makes the new variant more infectious than the original virus. 57 00:03:17,409 --> 00:03:22,374 N501Y also known as Nelly, is another spike protein mutation 58 00:03:22,374 --> 00:03:25,658 which appears to be associated with increased transmissibility. 59 00:03:25,658 --> 00:03:30,508 This mutation has been detected in the B.1.1.7, B.1.351 60 00:03:30,508 --> 00:03:34,779 and P.1 strains – all variants of concern. 61 00:03:34,779 --> 00:03:38,370 The worry of so-called ‘immune escape’ has also been hinted at 62 00:03:38,370 --> 00:03:43,610 with another spike protein mutation, E484K or Eek. 63 00:03:43,610 --> 00:03:47,235 Eek has been spotted in B.1.351 and P.1, 64 00:03:47,235 --> 00:03:50,020 the variants detected in South Africa and Brazil. 65 00:03:51,270 --> 00:03:55,238 Lab studies in early in 2021 showed that the variant could evade 66 00:03:55,238 --> 00:03:57,960 some virus-blocking antibodies, 67 00:03:57,960 --> 00:04:00,090 while trials in South Africa suggested 68 00:04:00,090 --> 00:04:03,610 that the variant reduced the efficacy of several vaccines. 69 00:04:04,590 --> 00:04:08,820 Despite these worries, the coronavirus is actually mutating very slowly 70 00:04:08,820 --> 00:04:11,514 compared to something like influenza 71 00:04:11,514 --> 00:04:14,079 and it seems like the vaccines developed so far 72 00:04:14,079 --> 00:04:16,699 will remain at least partly effective. 73 00:04:16,699 --> 00:04:21,774 But scientists are still taking the threat posed by variants seriously. 74 00:04:21,774 --> 00:04:25,639 And there are several things that can be done to help tackle it. 75 00:04:25,639 --> 00:04:30,000 Firstly, to do anything researchers need data. 76 00:04:30,000 --> 00:04:33,855 It’s very important to monitor and trace the emergence of variants 77 00:04:33,855 --> 00:04:35,858 and that isn’t always simple to do. 78 00:04:36,828 --> 00:04:41,938 Organisations like the COVID-19 Genomics UK consortium, or COG-UK, 79 00:04:41,938 --> 00:04:45,116 have stepped up their efforts to combine fast sequencing 80 00:04:45,116 --> 00:04:47,527 with efficient data sharing. 81 00:04:47,527 --> 00:04:52,410 COG-UK has already sequenced over 400,000 SARS-CoV-2 genomes. 82 00:04:53,330 --> 00:04:57,910 Next, researchers need to look forward to how these mutated viruses 83 00:04:57,910 --> 00:05:00,777 could affect global vaccination efforts. 84 00:05:00,777 --> 00:05:03,415 Existing vaccines can be redesigned 85 00:05:03,415 --> 00:05:06,617 and combinations of vaccines are also being tested 86 00:05:06,617 --> 00:05:10,493 but it could be difficult to perform reliable clinical trials 87 00:05:10,493 --> 00:05:13,340 amid the ongoing vaccination programmes. 88 00:05:14,290 --> 00:05:18,497 Right now though, work needs to continue at a national level. 89 00:05:18,497 --> 00:05:21,046 Public health policies such as track and trace, 90 00:05:21,046 --> 00:05:23,654 social distancing and vaccine roll-outs 91 00:05:23,654 --> 00:05:26,620 are powerful tools to interrupt transmission 92 00:05:26,620 --> 00:05:29,439 and keep tabs on new variants. 93 00:05:30,849 --> 00:05:34,441 After all, every time the virus is prevented from spreading, 94 00:05:34,441 --> 00:05:36,986 it's also prevented from mutating, 95 00:05:36,986 --> 00:05:41,525 nipping new variants in the bud before they even have a chance to develop.