The team also found that antibody levels rose with age, with people in the 60-85 age group displaying more than three times the amount of antibodies as people in the 15-39 age group.
The low amounts of antibodies could affect herd immunity, resistance to the disease among the general population to stop its spread.
The possibility not mentioned is that many people with similar symptoms to the Wuhan virus even in China may have had some other flu like virus.