This technique suggested to help fight the Coronavirus is not new. In fact, passive antibody therapy was the brainchild of the two scientists - Behring and Kitasato - who first discovered how certain antibodies in the blood help fight and develop an immunity to specific infectious diseases as far back as the 1890s. With time, scientists learned to collect those specific antibodies from the blood of patients who have recovered from the disease. They would inject people with these antibodies, which helped patients recover and this is how passive antibody therapy was born in the 1930s.
With time, the approach was abandoned, as antibiotics were becoming more popular. However, with the growing threat of antibiotic resistance and the emergence of new infectious diseases like the Coronavirus, passive antibody therapy has been experiencing a resurgence in the past few years. The approach is suggested to be effective at both preventing and treating infectious diseases.