A group from Weill Cornell Medicine, New York has reported on the relationship between serum IgG and Age with using serum samples gathered from April 2020 to June 2020.
https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2777743
The correlation diagram between serum IgG and Age using 85 SARS-CoV-2 positive pediatric and 3648 positive adult patient samples is shown below. The result is quite interesting. It is clearly found that the amount of serum IgG is inversely correlated with age at around 20 years old as a boundary. It remains unclear why patients aged 19 to 25 years exhibited lower levels of SARS-CoV-2 IgG antibodies than children and older adults.
