CCL4 and COVID-19: Patients infected with influenza (Uchide et al., 2012), COVID-19 (Rosen et al., 2022), Zika virus (Rabelo et al., 2020), dengue virus (Nunes et al., 2019), Chlamydia trachomatis of the reproductive tract (Faris et al., 2019), HIV (Akoto et al., 2021; Morrison et al., 2018), Plasmodium falciparum (Chêne et al., 2014; Dobaño et al., 2018), and latent tuberculosis (Indrati et al., 2022) had elevated levels of MIP1b, GROa, IL-8, RANTES, and IP10, but reduced levels of Eotaxin, MCP-1 (Requena et al., 2015), associated with the inflammation in the placenta.