Attempts by Oxford University researchers and AstraZeneca Plc. to create a nasal-spray version of their jointly developed COVID-19 shot suffered a setback on Tuesday as initial testing on humans did not yield the desired protection.
An antibody response in the respiratory mucous membranes was seen in only a minority of participants in the trial, which was in the first of usually three phases of clinical testing, the University of Oxford said in a statement on Tuesday.
