Monoclonal antibodies are synthetic proteins that mimic the immune system's ability to fight off harmful antigens such as viruses. Monoclonal antibodies to treat COVID-19 are directed against the spike protein of SARS-COV2, designed to block the virus' attachment and entry into human cells.
Early intervention with anti-SARS-CoV-2 monoclonal antibody treatment reduces the risk of severe illness and hospitalization in high-risk patients with mild to moderate COVID-19. Additionally, monoclonal antibody treatment can be used to decrease the chances of developing COVID-19 after an infectious exposure (as a post-exposure prophylaxis) in certain at-risk individuals.
The currently available anti-SARS-CoV-2 monoclonal antibodies that have received Emergency Use Authorization (EUA) from the Food and Drug Administration (FDA) include:
All three products cover current variants circulating in California.
| Casirivimab/Imdevimab (REGEN-COV) | Treatment of mild to moderate outpatients at risk of disease progression
Post-exposure prophylaxis in high-risk individuals | Yes
| Intravenous; subcutaneous | Federal government allocation of products to states based on previous week indicators; state-coordinated distribution system to facilities through local MHOACs |
Bamlanivimab/
Etesevimab | Treatment of mild to moderate outpatients at risk of disease progression
Post-exposure prophylaxis in high-risk individuals | Yes | Intravenous | Federal government allocation of products to states based on previous week indicators; state-coordinated distribution system to facilities through local MHOACs |
| Sotrovimab | Treatment of mild to moderate outpatients at risk of disease progression | Yes | Intravenous | Federal government allocation of products to states based on previous week indicators; state-coordinated distribution system to facilities through local MHOACs |
The EUAs for anti-SARS-CoV-2 monoclonal antibodies are for the treatment of mild to moderate COVID-19 in adults and pediatric patients (12 years of age and older weighing at least 40 kg) with positive results of direct SARS-CoV-2 viral testing, and who are at high risk for progressing to severe COVID-19 and/or hospitalization.
Timing: The treatment should be administered as soon as possible after positive results of direct SARS-CoV2 viral testing AND within 10 days of symptom onset. The California Department of Public Health (CDPH) recommends initiating treatment as soon as the positive results have been obtained, as early treatment is expected to have the most benefit.
High-risk criteria: include older age, being overweight/obese, pregnancy, chronic kidney disease, diabetes, immunosuppression, cardiovascular disease or hypertension, chronic lung diseases, sickle cell disease, neurodevelopmental disorders, having a medical-related technological dependence, or other medical conditions or factors (for example, race or ethnicity) that may also place individual patients at high risk for progression to severe COVID-19.
Authorization for use of monoclonal antibody treatment is not limited to the medical conditions or factors listed above. Healthcare providers should consider the benefit-risk for an individual patient.
Post-exposure prophylaxis: Both casirivimab plus imdevimab (REGEN-COV) (PDF)and bamlanivimab plus etesevimab (PDF) are authorized for use as a post-exposure prophylaxis of COVID-19 in adult and pediatric individuals (12 years of age and older weighing at least 40 kg) who are at high risk for progression to severe COVID-19.
Casirivimab plus imdevimab (REGEN-COV) (PDF) and bamlanivimab plus etesevimab (PDF) are authorized for use as a post-exposure prophylaxis for COVID-19 in adult and pediatric individuals (12 years of age and older weighing at least 40 kg) who are at high risk for progression to severe COVID-19.
Post-exposure prophylaxis can be considered in individuals who are not fully vaccinated or individuals who are not expected to mount an adequate immune response to SARS-CoV-2 vaccination (for example, individuals with immunocompromising conditions including those taking immunosuppressive medications).
Post-exposure prophylaxis can be given to these individuals if:
- They have been exposed to an individual infected with SARS-CoV-2 consistent with the Centers for Disease Control and Prevention (CDC) close contact criteria (less than 6 feet away from infected person for a cumulative total of 15 minutes or more over a 24-hour period); OR
- They are at high risk of exposure to an individual infected with SARS-CoV-2 because of occurrence of SARS-CoV-2 infection in other individuals in the same institutional setting.
For individuals who have recurrent exposures for a month or more, anti-SARS-CoV-2 monoclonal antibodies can be subsequently dosed every 4 weeks for the duration of the ongoing exposure.
Use of these products as post-exposure prophylaxis is not a replacement for vaccination. Additionally, the drug should not be used as a pre-exposure prophylaxis.
Anti-SARS-CoV-2 monoclonal antibody treatments are not authorized for use in patients who are:
- Hospitalized due to COVID-19, OR
- Require oxygen therapy due to COVID-19, OR
- Require an increase in baseline oxygen flow rate due to COVID-19 in those on chronic oxygen therapy due to underlying non-COVID-19 related morbidity
This treatment should only be administered in settings where health care providers have immediate access to medications to treat severe infusion reaction, such as anaphylaxis, and the ability to activate the emergency medical system, if necessary.
Given the limitations to using existing acute care hospital infrastructure during surges, CDPH encourages the use of these products in non-hospital outpatient settings (e.g., skilled nursing facilities, community clinics/FQHCs, state hospitals, jails, and other congregate/outpatient settings that have the required clinical capacity).
The EUAs for each monoclonal antibody product includes information on use criteria, preparation, and administration and can be found at the below links:
COVID-19 clinical treatment guidelines, including use of anti-SARS-CoV-2 monoclonal antibodies are available from National Institutes of Health (NIH) and Infectious Disease Society of America (IDSA).
Appropriate candidates should be referred to the nearest facility accepting patients for monoclonal antibody treatment. To find a location near you, here are two locator tools:
HHS has also created the "Combat Covid" webpage as a resource for your patients, this website includes a call center that patients can use to get more information regarding anti-SARS-CoV-2 monoclonal antibody treatment.
Anti-SARS-COV-2 monoclonal antibody products are available free of charge to facilities. Given high demand and limited supply, the U.S. Department of Health and Human Services (HHS) announced that effective September 13, 2021, distribution of anti-SARS-CoV-2 monoclonal antibody products will transition to a state/territory-coordinated distribution system. This means that facilities cannot directly order these products. At this time, there is no timeline for when direct ordering will be available.
Weekly distribution amounts of each anti-SARS-COV-2 monoclonal antibody product for each state/territory will be determined by HHS based on weekly reports of new COVID-19 cases and hospitalizations in addition to data on inventories and use submitted to the federal government.
CDPH will allocate product to local jurisdictions. Once the number of doses has been allocated, each jurisdiction's Medical and Health Operational Area Coordinator (MHOAC) will assist in determining which facilities within the jurisdiction receive product.
For facilities and healthcare providers interested in setting up infusions for high-risk patients with COVID-19, HHS Office of the Assistant Secretary for Preparedness and Response (ASPR) has many resources available. This includes a free COVID-19 monoclonal antibody therapeutics digital toolkit that your facility can use for social media platforms to help educate providers and patients. HHS has also created the "Combat Covid" webpage as a resource for your patients.
Additionally, if trying to set up a standalone Monoclonal Antibody Infusion Center, please see the Monoclonal Antibody Infusion Center Model (PDF). The mAbs Calculator can be used to inform staffing decisions and resource investments needed for COVID-19 monoclonal antibody therapeutic infusion sites.
HHS/ASPR also has a call center for questions and information related to monoclonal antibodies. Please share broadly with your networks of patients and providers.
- English: 1-877-332-6585
- Spanish:1-877-366-0310
Finally, particularly hard-hit local jurisdictions can submit resource requests through the California Governor's Office of Emergency Services (CalOES) for additional supplies and/or staffing. These requests can then be escalated to the appropriate state and federal authorities whereby they can assist with additional resources, if available.
The administration cost is billed through the usual claiming process, based on each patient's health care coverage.
For more information on reimbursement of monoclonal antibodies, please see: Reimbursement of COVID-19 Vaccine and Monoclonal Antibody Administration for Medical Providers .
For more information regarding Medicare coding and billing for monoclonal antibody infusions, please see: Monoclonal Antibody COVID-19 Infusion | CMS
HHS monitors utilization of anti-SARS-COV-2 monoclonal antibody products in California and uses these calculations to determine further allocation of these products to the state. Because of this, accurate reports of utilization are an important step in ensuring an appropriate supply to the state. Facilities using these products should make sure to account for utilization via HHS Protect or TeleTracking. See Reporting Utilization of COVID-19 Therapeutics for detailed instructions on reporting.
Originally Published on March 9, 2021