149 CMAAO CORONA FACTS and MYTH BUSTER Best time to donate plasma is 28 to 40 days
Dr K Aggarwal
971: COVID-19 Plasma Donors HAVE Higher Levels of IgG 28 DAYS After Symptom Onset
IgG in COVID-19 convalescent plasma donors appears to reach higher levels four weeks following onset of symptoms, suggesting that's the optimal time to collect plasma. In a study of 49 convalescent plasma donors, researchers found that plasma levels were lower when the donation occurred less than 28 days from the onset of symptoms compared to levels in patients who donated after four weeks, according to the results published in Transfusion.
Having had a fever lasting three or more days or a body temperature that exceeded 101.3 degrees F was also associated with increased IgG levels in the recovered patients.
Among the 49 convalescent plasma donors, 90% had a titer of >1:160 and 78% had a titer of ≥ 1:640.
Based on the selection criterion of donating plasma four weeks after the onset of symptoms, there were 42 convalescent plasma donors, of whom 90% had a titer of 1: 160 and 84% had a titer of ≥ 1:640. There was no correlation between S-RBD-specific IgG antibody and age, gender or donor blood type.
To take a closer look at donor characteristics, Dr. Li and colleagues recruited patients who had recovered from COVID-19, were aged 18 to 55 years, were eligible for blood donation, had two negative COVID-19 nasopharyngeal swab tests on PCR at least 24 hours apart, had been discharged from the hospital for more than two weeks and had no COVID-19 symptoms prior to donation.
IgG was measured with an ELISA assay that was developed in-house, and the researchers also confirmed the antibodies' neutralized SARS-CoV-2 in cell culture after five days.
One reassuring thing in the patients at Mount Sinai is that people over 65 also had high titers.