WEBVTT 00:00:00.299 --> 00:00:05.130 As the pandemic continues - variants have become the latest concern 00:00:05.130 --> 00:00:10.320 with notable examples detected in South Africa, Brazil and the UK. 00:00:10.320 --> 00:00:15.735 But variants are complicated. Each one is made up of a collection of mutations, 00:00:15.735 --> 00:00:22.379 all of which have the potential to change the SARS-CoV-2 virus in unexpected ways. 00:00:22.379 --> 00:00:26.030 So what do scientists mean when they talk about variants 00:00:26.030 --> 00:00:29.735 and what might this mean for the future of the pandemic? 00:00:30.854 --> 00:00:34.828 Viruses multiply by copying their genomes over and over. 00:00:34.828 --> 00:00:38.953 But like an old photocopier, these copies aren’t always perfect. 00:00:38.953 --> 00:00:42.996 Each of these imperfect copies is a variant. 00:00:43.120 --> 00:00:47.376 Normally the imperfections or mutations don’t change how the virus behaves 00:00:47.376 --> 00:00:51.780 and they can often make it less successful than the original strain. 00:00:51.780 --> 00:00:56.431 But very rarely mutations can change the virus in some important ways. 00:00:56.431 --> 00:01:03.199 It could become more infectious, or more able to avoid the immune system. 00:01:03.199 --> 00:01:06.000 The more a virus is allowed to replicate unchecked, 00:01:06.000 --> 00:01:10.680 the more chance it has to accumulate these rare beneficial mutations. 00:01:10.680 --> 00:01:15.871 That can occur when viruses are allowed to spread quickly through a population, 00:01:15.871 --> 00:01:18.554 or if they encounter a host that’s less able to fight them, 00:01:18.554 --> 00:01:24.417 such as people with compromised immune systems from medical treatment or those who are HIV+. 00:01:24.417 --> 00:01:31.180 If a particular set of mutations makes a variant more successful, it might become more prominent than others 00:01:31.180 --> 00:01:33.757 and that’s when it gets noticed. 00:01:33.757 --> 00:01:37.803 Epidemiologists may even decide to label it a ‘variant of concern’, 00:01:37.803 --> 00:01:42.330 like the examples identified in Brazil, South Africa and the UK. 00:01:42.330 --> 00:01:48.060 For months, scientists have been striving to work out what’s changed in these variants, 00:01:48.060 --> 00:01:50.060 and what those changes mean. 00:01:50.060 --> 00:01:56.180 Because a variant spreading doesn’t necessarily mean that it has an advantageous mutation. 00:01:56.180 --> 00:02:01.320 For example a small number of people could, by chance, move a variant from one region 00:02:01.320 --> 00:02:06.310 to another, like tourists travelling back from popular vacation spots. 00:02:06.310 --> 00:02:09.592 This could cause that variant to start spreading in a new location 00:02:09.592 --> 00:02:13.794 even though there may be no significant change to the biology of the virus. 00:02:13.794 --> 00:02:17.200 This is called the Founder Effect. 00:02:17.200 --> 00:02:21.828 Understanding why a variant has emerged requires a combination of studies. 00:02:21.828 --> 00:02:28.939 Epidemiology can help detect and trace new variants and flag new or worrying patterns of infection. 00:02:28.939 --> 00:02:35.666 Meanwhile lab studies can start to pinpoint how the mutations are changing the properties of the virus. 00:02:35.666 --> 00:02:42.043 And studies like these are starting to identify mutations that have given the virus an upper hand. 00:02:42.043 --> 00:02:46.940 Some variants are faster spreading, and there are hints that certain mutations 00:02:46.940 --> 00:02:52.510 could start to weaken or even evade natural and vaccine derived immunity. 00:02:52.510 --> 00:02:58.470 For example, the D614G mutation, known to virologists as Doug, spread widely in the 00:02:58.470 --> 00:03:02.290 early days of the pandemic and can be seen in almost all variants. 00:03:02.290 --> 00:03:08.440 It affects the spike protein that coronavirus particles use to penetrate cells. A mutation 00:03:08.440 --> 00:03:11.246 in the genome changes one amino acid for another, 00:03:11.246 --> 00:03:17.409 and makes the new variant more infectious than the original virus. 00:03:17.409 --> 00:03:25.658 N501Y also known as Nelly, is another spike protein mutation which appears to be associated with increased transmissibility. 00:03:25.658 --> 00:03:34.599 This mutation has been detected in the B.1.1.7, B.1.351 and P.1 strains - all variants of concern. 00:03:34.599 --> 00:03:43.610 The worry of so-called ‘immune escape’ has also been hinted at with another spike protein mutation, E484K or Eek. 00:03:43.610 --> 00:03:51.270 Eek has been spotted in B.1.351 and P.1, the variants detected in South Africa and Brazil. 00:03:51.270 --> 00:03:57.960 Lab studies in early in 2021 showed that the variant could evade some virus-blocking antibodies, 00:03:57.960 --> 00:04:04.590 while trials in South Africa suggested that the variant reduced the efficacy of several vaccines. 00:04:04.590 --> 00:04:09.820 Despite these worries, the coronavirus is actually mutating very slowly compared to 00:04:09.820 --> 00:04:16.699 something like influenza and it seems like the vaccines developed so far will remain at least partly effective. 00:04:16.699 --> 00:04:21.774 But scientists are still taking the threat posed by variants seriously. 00:04:21.774 --> 00:04:25.639 And there are several things that can be done to help tackle it. 00:04:25.639 --> 00:04:30.000 Firstly, to do anything researchers need data 00:04:30.000 --> 00:04:37.169 - it’s very important to monitor and trace the emergence of variants and that isn’t always simple to do. 00:04:37.169 --> 00:04:41.668 Organisations like the COVID-19 Genomics UK consortium, or COG-UK, 00:04:41.668 --> 00:04:47.527 have stepped up their efforts to combine fast sequencing with efficient data sharing. 00:04:47.527 --> 00:04:53.330 COG-UK has already sequenced over 400,000 SARS-CoV-2 genomes. 00:04:53.330 --> 00:04:58.910 Next, researchers need to look forward to how these mutated viruses could affect global 00:04:58.910 --> 00:05:06.617 vaccination efforts. Existing vaccines can be redesigned and combinations of vaccines are also being tested 00:05:06.617 --> 00:05:14.290 but it could be difficult to perform reliable clinical trials amid the ongoing vaccination programmes. 00:05:14.290 --> 00:05:18.497 Right now though, work needs to continue at a national level. 00:05:18.497 --> 00:05:23.654 Public health policies such as track and trace, social distancing and vaccine roll-outs 00:05:23.654 --> 00:05:30.849 are powerful tools to interrupt transmission and keep tabs on new variants. 00:05:30.849 --> 00:05:34.441 After all, every time the virus is prevented from spreading, 00:05:34.441 --> 00:05:36.986 it's also prevented from mutating, 00:05:36.986 --> 00:05:41.525 nipping new variants in the bud before they even have a chance to develop.