Another study showed that the S1-IgA positive rate of patients with mild COVID-19 was 92% at 6 weeks after the onset, which dropped to 78% after 6 months with a decrease in titer of about 50%, and while at 12 months, there was still a 78% positive rate and the titer was not significantly different from that at 6 months (29). The gene discussed is CD79A; the disease is COVID-19.