The first step was not an easy one: Training dogs to remain absolutely still in a functional magnetic resonance imaging (fMRI) scanner. It took several months for dog trainers to work their magic on 13 pet dogs that live in Hungary, including six border collies, four golden retrievers, one German shepherd, and one Chinese crested.
"The game-changer is that you could distribute the [powder] vaccine extremely easily without the cold chain, and it can be administered without the need for healthcare providers," says ISR's founder, Ola Winquist, a professor of immunology at the Karolinska Institute, one of Sweden's leading medical universities.
But, Mr Downham says, work also needs to be done to ensure vaccine makers are using their full capacity at all times. For example, if a manufacturer's "fill and finish" services - when vaccines are bottled and packed - are not available, there need to be ways of using other available facilities to ensure manufacturing doesn't slow down or come to a halt.
Lead investigator Prof Matthew Snape, from the University of Oxford, said the findings did not undermine the UK policy of giving people the same jab twice: "We already know that both standard schedules are very effective against severe disease and hospitalisations, including against the Delta variant when given at eight to 12 weeks apart."
They then tested the models on an external test set of 129 paired radiographs from patients at Johns Hopkins University who were diagnosed with sarcoidosis involving any organ. The test set had a higher prevalence of hilar adenopathy compared with the general population, Mazumdar noted. For the purposes of the study, the ground truth was determined by board-certified thoracic radiologists after reviewing contemporaneous chest CT images.