"On the other hand, among those who did have the illness (based on symptoms), it would appear that overall greater than 70% of them developed antibodies"
Unless im reading it wrong, many did not get tested for Covid19 and only had Symptoms.
I agree that it isn't reflective of the broader population, but one could argue that those same numbers would be reflected among the asymptomatic.
Which numbers? 100% of people who were positive with Corona are positive on the Roche antibodies test.
I'm not sure whoever wrote that article actually understood what he's trying to say, but he seems to claim from all of the 3500 in the survey with presumed Covid, seemingly defined by having symptoms, 70% had antibodies, which means 30% never had Corona. What exactly can you extrapolate from that to asymptomatic patients?