CD40LG and infection: Furthermore, the increase in the IgM antibody, which is present in acute or recent infections, produced on average seven days after the onset of symptoms [48], may be associated with the presence of a more significant number of unvaccinated individuals in group B (municipalities with a lower vaccination rate), a fact that may increase the chances of the virus circulating, through contamination via aerosols, surfaces, and direct contact in the case of family members of infected individuals [49].