This is based off the assumption that 25% of healthcare workers could have been exposed, but they only detected antibodies in 4%. Haven't there been recent stud

This is based off the assumption that 25% of healthcare workers could have been exposed, but they only detected antibodies in 4%. Haven't there been recent studies in the US showing that infection rates among healthcare workers are low? It seems more likely to me that the 25% estimate is just way off.