This article analyzes the possibility of employing immunotherapy and preventive immunization to fight COVID-19. The authors think that treatment and prevention of the infection with anti-SARS-CoV-2 antibodies can have unpredictable outcomes. Although these antibodies can neutralize virus antigens (S-proteins), they also have the ability to enhance virus entry into the host cell. The article emphasizes the importance of solid evidence of efficacy and safety for candidate anti-COVID-19 therapies and protective measures. © 2020 Pirogov Russian National Research Medical University. All rights reserved.