SharecloseShare pageCopy linkAbout sharingCatching Covid may cause changes to the brain, a study suggests.Scientists found significant differences in MRI (magnetic resonance imaging) scans before and after infection.Even after a mild infection, the overall size of the brain had shrunk slightly, with less grey matter in the parts related to smell and memory.The researchers do not know whether the changes are permanent but stressed the brain could heal.The study is published in the journal Nature.Lead author Prof Gwenaelle Douaud, from the Wellcome Centre for Integrative Neuroimaging, at the University of Oxford, said: “We were looking at essentially mild infection, so to see that we could really see some differences in their brain and how much their brain had changed compared with those who had not been infected was quite a surprise.”The UK Biobank project has followed the health of 500,000 people for about 15 years and has a database of scans recorded before the pandemic so provided a unique opportunity to study the long-term health impacts of the virus. The scientists rescanned:401 participants 4.5 months, on average, after their infection, 96% of whom had had mild Covid 384 participants who had not had CovidThey found:The overall brain size in infected participants had shrunk between 0.2 and 2%There were losses in grey matter in the olfactory areas, linked to smell, and regions linked to memoryThose who had recently recovered from Covid found it a bit harder to perform complex mental tasksBut the researchers do not know whether the changes are reversible or truly matter for health and wellbeing.”We need to bear in mind that the brain is really plastic – by that we mean it can heal itself – so there is a really good chance that, over time, the harmful effects of infection will ease,” Prof Douaud said.The most significant loss of grey matter was in the olfactory areas – but it is unclear whether the virus directly attacks this region or cells simply die off through lack of use after people with Covid lose their sense of smell.It is also unclear whether all variants of the virus cause this damage. The scans were performed when the original virus and alpha variant were prevalent and loss of smell and taste a primary symptom. But the number of people infected with the more recent Omicron variant reporting this symptom has fallen dramatically.’Your mind is what is being exercised’Paula Totaro lost her sense of smell when she caught Covid, in March 2020.”When it was gone, it was like living in a bubble or a vacuum – I found it really isolating,” she told BBC News.But after contacting the charity AbScent, which supports people who have lost their ability to smell and taste, she began smell training.”What smell training does – particularly if you do it twice a day, regularly, religiously – is it forces you to take the smell, allow it to go back into your nose and then to think about what it is that you’re smelling,” she said.”And that connection between what’s in the external world and what goes into your brain and your mind is what is being exercised.”Ms Totaro has now recovered most of her sense of smell – although she still has trouble identifying what different smells are.”It’s a mix of joy that the sense has come back but still a little bit of anxiety that I’m not quite there yet,” she said.UK Biobank chief scientist Prof Naomi Allen said: “It opens up all sorts of questions that other researchers can follow up about the effect of coronavirus infection on cognitive function, on brain fog and on other areas of the brain – and to really focus research on how best to mitigate that.”Prof David Werring, from the University College London Institute of Neurology, said other health-related behaviour could have contributed to the changes seen. “The changes in cognitive function were also subtle and of unclear relevance to day-to-day function,” he said.”And these changes are not necessarily seen in every infected individual and may not be relevant for more recent strains.”Follow @BBCMorelle on Twitter.More on this storyScans aim to reveal Covid health legacyUK BiobankWellcome Centre for Integrative NeuroimagingAbScentNature: SARS-CoV-2 is associated with changes in brain structure in UK BiobankThe BBC is not responsible for the content of external sites.

SharecloseShare pageCopy linkAbout sharingimage copyrightReutersThe harrowing scenes from India have shocked the world, as the country struggles with soaring cases of Covid. But the outbreak isn’t just a crisis for India – it’s a crisis for everyone.”The virus doesn’t respect borders, or nationalities, or age, or sex or religion,” says Dr Soumya Swaminathan, the World Health Organization’s chief scientist.”And what’s playing out in India now unfortunately has been played out in other countries.”A visual guide to the Covid crisis in IndiaWhy India’s vaccine manufacturers need US help The pandemic has revealed just how interconnected the world is. And if a country has very high levels of infection, then it’s likely to spread to other countries. Even with travel restrictions, multiple tests and quarantine, infections can still leak out; and if a traveller has come from somewhere where the virus is very prevalent, they have a higher chance of taking the virus with them. On a recent flight from New Delhi to Hong Kong about 50 passengers tested positive for Covid-19.But there’s another concern with India’s high infection rates: variants.A new variant has emerged in India called B.1.617. It’s been dubbed by some as the “double mutant” because of two key mutations on the spike of the virus. There’s some lab evidence that suggests it’s slightly more transmissible and that antibodies may find it harder to block the virus, but scientists are still assessing how much immunity is lost. “I don’t think there’s any evidence that it’s an escape mutation [which would mean] it fundamentally can’t be stopped by the vaccines,” Dr Jeff Barrett, director of the Covid-19 Genomics Initiative at the Wellcome Sanger Institute, told BBC News. “I think we have to obviously watch carefully, but there’s at present no reason to panic about it.”‘We called 200 people to find a hospital bed’What is the India Covid variant?But the higher the number of Covid cases a country has, the more likely it is that new variants will emerge. That’s because every single infection gives the virus a chance to evolve and a major concern is that mutations could arise that render vaccines ineffective.”The way to limit viral variants emerging in the first place is to prevent the virus replicating in us… so the best way to control variants is actually to control the global amount of disease that we have at the moment,” explains Prof Sharon Peacock, Director of the Covid-19 Genomics UK consortium (Cog-UK).Lockdowns and social distancing measures will do this – but vaccination is also vital.This is happening slowly in India: so far less than 10% of its population have had the first dose of the vaccine and less than 2% are fully vaccinated. This is despite the fact that it’s home to the world’s biggest vaccine manufacturer – the Serum Institute of India. And this is another reason why India’s surge in cases has a knock-on effect for the rest of the world.

Getty ImagesTop Indian Covid vaccine makersSIICovishield, NovavaxBharat BiotechCovaxin, CoraVaxBiological EJohnson & JohnsonZydus CadilaZyCoV-DHetero BiopharmaSputnik VDr Reddy’s LabSputnik VSource: Media reportsIn March, as infections in India started to surge, authorities there halted large exports of the Oxford-AstraZeneca vaccine.That included vaccines for the UN-backed Covax scheme to provide doses to low and middle-income countries. On Monday, the Global Vaccine Alliance (Gavi), which is a partner in the scheme, said it was waiting to hear when supplies from India would resume. This will certainly impact on vaccination roll-outs in many countries. But it means more of India’s vaccines are diverted for domestic use, while it tries to ramp up production.And with India’s dire situation, scientists say this is a priority.”We really need to double down on vaccination as quickly as possible or the virus is going to try and do everything it can to keep on spreading from person to person,” says Swaminathan.Globally, the pandemic shows no sign of easing, with the virus devastating country after country.The situation in India is a bleak reminder that none of us will be safe until everyone is safe.Follow Rebecca on Twitter