COVID-19 drugs - what is known by now?

Coronavirus disease 2019 (COVID-19), caused by the SARS-CoV-2 virus, has significantly impacted global health, resulting in over 240 million cases and nearly 5 million deaths as of October 2021. This infectious disease shares about 80% of its genome with SARS-CoV, identified in China in 2002-2003. As the pandemic persists, there has been an urgent need for effective diagnostics, vaccines, and therapeutic drugs. Drug development efforts for COVID-19 are broadly categorized into four areas: drug repurposing, monoclonal antibody development, convalescent plasma therapy, and novel drug development. 
Drug repurposing involves using existing drugs for new therapeutic purposes. Noteworthy candidates include remdesivir, originally for Ebola, and lopinavir/ritonavir, used for HIV. Remdesivir has shown varying levels of efficacy, particularly effective in early-stage COVID-19.
Monoclonal antibodies, such as REGEN-COV and bamlanivimab, have been rapidly developed and authorized for emergency use. These antibodies inhibit the virus by targeting its spike protein, preventing cell entry. Despite their effectiveness, high costs and production challenges limit their broader application.
Convalescent plasma therapy leverages antibodies from recovered patients, though large-scale trials have not demonstrated significant benefits for severe cases. The variability in antibody levels among donors and logistical issues pose significant obstacles.
New antiviral drugs are also in development, including Merck’s molnupiravir and Pfizer’s PF-07321332. Molnupiravir, an oral medication, has shown a 50% reduction in hospitalization risk in clinical trials. PF-07321332 targets viral protease, crucial for virus replication.
Overall, these diverse strategies underscore the importance of a multifaceted approach in combating COVID-19. Continuous research and development are essential to address emerging variants and ensure global accessibility.