The Novavax coronavirus trial threatens to descend into chaos as exasperated volunteers say they will drop out because they cannot prove they are fully vaccinated on the NHS app, leaving them unable to travel to Europe. Among the 15,000 volunteers who took part, many say they are considering quitting or getting alternative jabs – despite the potential health risks – because the vaccine passport function on the app is not properly set up to accommodate them. People in England who have had two doses of an approved coronavirus vaccine were able to use the NHS app to confirm their vaccine status for international travel this week. But the app is unable to display details of those who have had their jabs as part of a clinical trial, with frustrated participants left feeling “disadvantaged” as a result. Christina Boissy-Parker, 46, a French native from London, said she wanted to see her family and that is why she took part in the trial. “We are not even on the NHS app that shows people have received a vaccine. I have received an A4 poster showing my vaccination, but anybody could forge this, so it won’t be accepted as proof,” she said. Boissy-Parker said she regretted her choice in joining the trial and is now considering getting the NHS vaccine. “Because I had two doses only five and two weeks ago, I’m worried about the consequences on my health having too many doses in a short time. But if it is the price to pay to see my family, then I won’t have any choice.” One participant who asked to remain anonymous, 37, from Poulton le Fylde in the north-west of England, said he volunteered for the Novavax vaccine clinical trial and spent time over the last eight months having vaccines or placebos administered along with multiple blood samples for research. “Having contacted the NHS to confirm my vaccination status, I have now been informed that I am not considered as being vaccinated under the Novavax trial as it is yet to be approved,” he said. “I am seriously concerned and astonished that I have been fed such wildly misleading information as to how my participation in the trial would affect me.” He said that in a Facebook group of Novavax participants, many were “contacting the Covid centres and having another vaccine” – without “informing them that they have participated in the Novavax trial”. “The health implications of this could be enormous,” he added. Volunteers were advised not to seek an alternative vaccine. The gap between two doses of vaccine is 12 weeks in the UK. The participant said he needed to travel for work and had he known of the potential issues of being involved in the trial he would not have considered it. Tony Irwin, 78, is in the vulnerable group and said he had a second jab on 9 December 2020. “The length of time not knowing if the vaccine is going to pass the regular is excessive,” he said. It was reported in March that the UK enrolled 15,203 participants in the Novavax phase 3 Covid-19 vaccine trial in two months. Novavax will not file for approval of its Covid-19 vaccine until July at the earliest, due to manufacturing issues related to an assay needed to show regulators its vaccine manufacturing process is consistent across different sites. On its website, the National Institute for Health Research said it did not want people to feel “disadvantaged”. It said: “As you are aware from the media, plans are under way to recognise vaccine status and have it displayed on the NHS app.” It added: “The government is working at speed to make sure that records for trial participants are transferred to the data systems the NHS app uses to demonstrate vaccine status. This is expected to be in place by the time the government next reviews entry requirements.” A government spokesperson said: “We are working to ensure those who volunteered to receive a test Covid-19 vaccine in a clinical trial, where that vaccine has now been approved, are able to access their vaccine status via the NHS App or by calling 119.”