CD40LG and pneumonia: Moreover, as shown in Table 1, nonpneumonia cases, compared to pneumonia cases, were associated with prolonged disease courses (>8 weeks, 29.8% vs 0%, P = 9.06 × 10−9) and impaired IgG seroconversion (i.e., higher IgM (+) IgG (−) [28.6% vs 4.1%, P = .004] and lower IgM (−) IgG (+) [14.3% vs 55.1%, P = 5.91 × 10−4]) during recovery (7‐8 weeks post disease onset), suggesting insufficient virus‐specific antibody response and potential latent infection.