Even as scientists race to develop a Covid-19 vaccine, nations are vying to grab huge supplies before anyone else. Australia has just become the latest, having signed deals securing 85 million vaccine doses – more than triple its population. But the scramble for supplies is sparking accusations of “vaccine nationalism” with poor countries being left behind, and fears that politics rather than science is influencing vaccine development. The global effort to develop a Covid-19 vaccine began in January, just days after the disease was identified. But fears quickly emerged that rich countries would hoard the first supplies to treat their own populations – as happened with early treatments for the disease. In an attempt to head off the problem, in April the World Health Organisation introduced Covax, a global initiative to support vaccine research with the aim of getting two billion doses to every nation by the end of 2021. So far, 172 countries have signed up. While more than 160 vaccines are in development around the world, the vast majority are expected to fail. Only a handful are serious contenders in the race – and the governments of rich nations are paying billions to get to the front of the queue for the first supplies. According to an analysis by the <em><a href="https://www.wsj.com/articles/in-race-to-secure-covid-19-vaccines-worlds-poorest-countries-lag-behind-11598998776" target="_blank">Wall Street Journal</a></em>, the US, EU, Japan and the UK together have options to buy more than 3.7 billion doses from western pharmaceutical companies – locking up most of the world's production capacity. The UK government is currently the biggest player, having signed deals for <a href="https://www.ft.com/content/1e928cb6-57fb-4384-9c2c-9000c44eacc0" target="_blank">hundreds of millions of doses spread across several candidate vaccines</a> – including one developed by the University of Oxford and AstraZeneca, which remains a strong contender despite one <a href="https://www.thenational.ae/world/the-americas/astrazeneca-pauses-vaccine-study-after-volunteer-falls-ill-1.1074895">volunteer becoming ill</a> among the tens of thousands currently involved in international trials, which have now been paused pending safety checks. Partly because governments need to hedge their bets: no one knows which vaccine will work. The Oxford/AstraZeneca vaccine is based on genetically modified human cells with coronavirus-like characteristics. Once injected into patients, these can train the immune system to recognise and defeat the real virus. Another UK deal involves a more conventional vaccine being developed in France, using a real but deactivated Covid-19 virus. Even if these vaccines do work, they may need more than one dose, and possibly also boosters – pushing demand higher. Vaccines are usually clinically tested on tens of thousands of people before being approved for general use. Yet even the most thorough trials lack the power to detect unusual side effects – especially among the vulnerable, who are usually excluded from such testing. With billions of people ultimately needing protection, a 99.99 per cent safe vaccine could still lead to hundreds of thousands of seriously ill people globally. Leading public health experts have called for nations to show fairness in their use of the first supplies of the vaccine. Jeremy Farrar, director of the UK charity Wellcome Trust, made a public plea in <em>The Guardian </em>for nations to put frontline healthcare workers and the most vulnerable ahead of the general population. However, the UK has yet to commit to pooling any surplus supplies, while the US and Russia have both declined to join the Covax initiative, relieving them of any obligations. If President Vladimir Putin is to be believed, it already is: last month he declared that Russia had become the <a href="https://www.thenational.ae/world/europe/russia-starts-production-of-covid-19-vaccine-1.1063870">first country to approve a Covid-19 vaccine</a>. Dubbed Sputnik-V, it is already being administered to volunteers – including one of Mr Putin's daughters. The announcement was greeted with scepticism by independent experts, underlined by the <a href="https://www.thenational.ae/world/europe/russian-covid-19-vaccine-induces-antibody-response-1.1072955" target="_blank">results from a small trial published in <em>The Lancet</em></a><em>. </em> Confusion also surrounds US President Donald Trump's <a href="https://www.thenational.ae/world/trump-says-us-could-have-covid-19-vaccine-by-october-1.1074314">announcement this week</a> that "We'll have the vaccine soon, maybe before a special date. You know what date I'm talking about" – taken by many to be a reference to November 3, the date of the US presidential election. US health officials familiar with Operation Warp Speed – the US vaccination development programme – have downplayed such a possibility. The most promising candidate remains the Oxford/AstraZeneca vaccine, with the pause in international trials expected to be temporary and <a href="https://www.bbc.co.uk/news/world-54082192">possibly ending in a matter of days</a>. An effective vaccine will certainly be a major step towards controlling the virus. However, health experts insist the pandemic will only end if the vaccine is globally available. As the emergence of Covid-19 showed, just a small outbreak in one country can lead to catastrophe. <a href="https://www.euronews.com/2020/08/18/coronavirus-19-european-countries-record-high-incidence-rates-as-surge-continues" target="_blank">Calling for a collective global response</a>, WHO director general Tedros Adhanom Ghebreyesus said: "No one is safe until everyone is safe." <em>Robert Matthews is visiting professor of science at Aston University, Birmingham, UK</em>