Senior government science advisers from the UK, Europe and Canada have called on countries around the world to offer vaccination certificates to volunteers on Covid jab trials so they can travel internationally.The UK has led the way in granting vaccine certificates to trial participants, but many countries have failed to follow suit and refuse to admit people unless they have had two doses of Covid vaccine that has already gone through trials and been approved by regulators.The situation means many tens of thousands of people globally who enrolled in clinical trials to assess Covid vaccines, or combinations of different shots, cannot travel abroad unless they get an additional round of approved jabs.In an open letter to governments around the world 14 senior advisers, including England’s chief medical officer, Prof Chris Whitty, and the UK’s chief scientist, Sir Patrick Vallance, warn that preventing trial volunteers from travelling was “unfair” and had led some participants to drop out of trials and seek extra vaccinations.“Vaccine clinical trial volunteers have given their time freely to help others, and clinical trials are the way in which the world can understand which vaccines work and are safe,” the letter states. “There is a moral and ethical obligation to treat volunteers in a way that feels fair to them and to the wider public. It is the right thing to do.”Among those affected are more than 15,000 people who took part in the phase 3 Novavax trial at hospitals across the UK. The firm has not yet submitted the trial data to regulators for approval.Kris Gumbrell, the chief executive officer of a pub chain, took part in the Novavax trial and received four shots in total, two vaccine, two placebo, between October 2020 and April 2021. He has a vaccine certificate that can be used to enter events in the UK, but he cannot travel to any country that requires approved vaccines. To complicate matters further, the NHS app considers him vaccinated so he cannot book the extra shots he now wants so he can travel with his family in January.“You hit a brick wall because your Novavax vaccination doesn’t count. You’re stuck in this trap. You can’t go anywhere that requires an approved vaccine,” Gumbrell said. “There’s an awful lot of upset people out there. The UK has done a huge amount of heavy lifting with vaccine trials. The politicians should be fighting our corner more.”In an effort to find a solution, the UK government announced last week that it would provide two shots of the approved Pfizer/BioNTech vaccine for thousands of Britons who took part in trials so they could travel abroad – meaning they would have four shots of Covid vaccine total.The letter urges foreign governments to issue vaccine certificates or “passports” to volunteers on vaccine trials that have been approved by regulators, regardless of whether the participants have received unlicensed vaccines, combinations of shots, or even placebo jabs.“Given the numbers of trial participants globally, the population contribution of admitting a small number of placebo recipients in trials will be trivial in terms of public health and national disease epidemiology,” the letter states.“Of course trials will continue to be needed to improve vaccine design and coverage, especially as the virus mutates and evolves. Anything that acts as a disincentive to participate in trials will be to the detriment of public health,” it adds.Prof Saul Faust, the Wessex regional lead for Covid vaccine trials at the University of Southampton, said the letter was “a massively important intervention” by Chris Whitty and his colleagues.“Vaccine trial participants – of whom there are more than 50,000 in the UK but many tens of thousands more globally – have been discriminated against as second class citizens by politicians globally instead of treated as the heroes they are. Without them we would have no vaccines at all,” Faust said. “While the UK decided to honour participants with UK accreditation before the summer, because no other countries have agreed this principle none of our UK participants have been able to travel or go abroad so far without lying to get extra doses of approved vaccines – also at considerable personal risk as the effects of such combinations or doses are unknown.”“If governments don’t sort this out, no one will ever want to take part in trials again, so booster trials and of any future pandemic vaccines will be at risk,” he added.