If Prasad thought this needed more research then it needed more research. He and the people he works with have written dozens, maybe hundreds now, of reports that expose studies that lack the rigor for definitive results, have misleading endpoints, have imbalanced arms etc. I get that anything that would slow vaccines down has somehow become political and lots of people would gladly accept the pharmaceutical companies word on things. This is a blindness due to political leanings and not evidence based. If Prasad says it needs more and better data I'd put money on it needing it.