COVID-19 public health policy has focused on the SARS-CoV-2 virus and its effects on human health while environmental factors have been largely ignored. In considering the epidemiological triad (agent-host-environment) applicable to all disease, we investigated a possible environmental factor in the COVID-19 pandemic: ambient radiofrequency radiation from wireless communication systems including microwaves and millimeter waves. COVID-19 surfaced in Wuhan, China shortly after the implementation of city-wide 5G (fifth generation of wireless radiation), and spread globally, demonstrating a statistical correlation to international communities with 5G antennas installed. In this study, we examined the peer-reviewed scientific literature on the detrimental bioeffects of radiofrequency radiation (RFR) and identified several ways in which RFR may be contributing to COVID-19 as a toxic environmental cofactor. We conclude that RFR and, in particular, 5G, which involves 4G infrastructure densification, has exacerbated COVID-19 prevalence and severity by weakening host immunity and increasing SARS-CoV-2 virulence by (1) causing morphologic changes in erythrocytes including echinocyte and rouleaux formation that may be contributing to hypercoagulation; (2) impairing microcirculation and reducing erythrocyte and hemoglobin levels exacerbating hypoxia; (3) amplifying immune system dysfunction, including immunosuppression, autoimmunity, and hyperinflammation; (4) increasing cellular oxidative stress and the production of free radicals exacerbating vascular injury and organ damage; (5) augmenting intracellular Ca2+ essential for viral entry, replication, and release, in addition to promoting pro-inflammatory pathways; and (6) worsening heart arrhythmias and cardiac disorders. In short, RFR is a ubiquitous environmental stressor that contributes to adverse health outcomes of COVID-19. We invoke the Precautionary Principle and strongly recommend a moratorium on 5G wireless infrastructure at this crucial time to help mitigate the pandemic, and to preserve public health until governmental safety standards for RFR exposure based on current and future research are defined and employed.