CD40LG and dengue disease: Out of 238 dengue collected before the pandemic, 6.7 % (16/238) samples were reactive to SARS-CoV-2 antibodies, in detail 2.1 % (5/238) IgG+/IgM-, 4.2 % (10/238) IgG-/IgM+, 0.4 % (1/238) IgG+/IgM+.