Figure 2.

Dynamics of the IgG positive rate and antibody levels during the two follow-up rounds. The length of follow-up ranged from 5.4 months to 17.4 months. At two-month intervals, the horizontal axis has been divided into seven equal parts, 5~6 months, 7~8 months, 9~10 months, 11~12 months, 13~14 months, 15~16 months and 17~18 months. (A) Trends in IgG positive rate over months after symptom onset in overall, unvaccinated and vaccinated convalescent patients. (B) Trends in IgG antibody levels over months after symptom onset in overall, unvaccinated and vaccinated convalescent patients. (C) Trends in neutralising antibody levels over months after symptom onset in overall, unvaccinated and vaccinated convalescent patients. P values were determined applying a two-tailed Mann-Whitney U test. P<0.05 was considered to be statistically significant.