key: cord-0981474-mof7tf6m
authors: Flaxman, Abraham D.; Issema, Rodal; Barnabas, Ruanne V.; Ross, Jennifer M.
title: Estimated Health Outcomes and Costs of COVID-19 Prophylaxis With Monoclonal Antibodies Among Unvaccinated Household Contacts in the US
date: 2022-04-22
journal: JAMA Netw Open
DOI: 10.1001/jamanetworkopen.2022.8632
sha: a667fb3255e8245d0e52857dbf273ee140a1eb1b
doc_id: 981474
cord_uid: mof7tf6m

IMPORTANCE: The COVID-19 pandemic has led to more than 900 000 deaths in the US and continues to disrupt lives even as effective vaccines are available. OBJECTIVE: To estimate the health outcomes and net cost of implementing postexposure prophylaxis (PEP) with monoclonal antibodies (mAbs) against household exposure to COVID-19. DESIGN, SETTING, AND PARTICIPANTS: This study is a decision analytical model of results from a randomized clinical trial of casirivimab with imdevimab administered as subcutaneous injections to unvaccinated, SARS-CoV-2–negative household contacts of people with confirmed COVID-19 with complementary data on household demographic structure, vaccine coverage, and confirmed COVID-19 case counts. The study used US data from May 2021 for a simulated population of US individuals of all ages within low-transmission or high-transmission scenarios. EXPOSURES: Age, sex, race, ethnicity, and COVID-19 vaccination status. MAIN OUTCOME OR MEASURES: Symptomatic infection, hospitalization, death, and net payer cost of monoclonal antibody PEP for COVID-19. RESULTS: In a month of transmission intensity similar to that of May 2021, a mAb PEP program reaching 50% of exposed, unvaccinated household members aged 50 years and older was estimated to avert 1820 symptomatic infections (95% uncertainty interval [UI], 1220-2454 symptomatic infections), 528 hospitalizations (95% UI, 354-724 hospitalizations), and 84 deaths (95% UI, 55-116 deaths) in a low-transmission scenario and 4834 symptomatic infections (95% UI, 3375-6257 symptomatic infections), 1404 hospitalizations (95% UI, 974-1827 hospitalizations), and 223 deaths (95% UI, 152-299 deaths) in a high-transmission scenario. Without mAb PEP, the estimated cost of hospitalizations due to COVID-19 infections from household exposure in the lower transmission scenario was $149 million (95% UI, $115-$196 million), whereas the estimated hospitalization cost in the higher transmission scenario was $400 million (95% UI, $312-$508 million). In the lower transmission scenario, mAb PEP administered to 50% of eligible contacts aged 80 years and older was estimated to have 82% probability of saving costs, but was not associated with cost savings at age thresholds of 50 years and older or 20 years and older. In contrast, in the high-transmission scenario, mAb PEP administered to 50% of eligible household contacts had estimated cost savings in 100% of simulations at the 80-year age threshold, 96% of simulations at the 50-year threshold, and 2% of simulations at the 20-year thresholds. CONCLUSIONS AND RELEVANCE: In this modeling study of a simulated US population, a mAb PEP for COVID-19 program was estimated to improve health outcomes and reduce costs. In the setting of a susceptible variant of SARS-CoV-2, health system and public health actors would have an opportunity to improve health and reduce net payer costs through COVID-19 PEP with mAbs.

where mAbs and hosp are the unit costs for mAbs and COVID-19 hospitalization.

Parameters, values, data sources, and analytical methods: • 1 ( , , ) comes from CDC confirmed cases; to deal with missing data, we computed the fraction of cases by age, sex, and race/ethnicity from the rows with complete data (complete-case analysis) and then scaled this value to the total number of cases detected during May 2021. We selected age groups to match those available in the CDC data, and collapsed race/ethnicity to white, Black, Hispanic, and all other race/ethnicities. 1 • ℎℎ ′ , ′ , ′ ( , , ) comes from ACS PUMS data, which includes age in years, sex, race/ethnicity, and household ID. 2 • We examined scenarios corresponding to all combinations of the age thresholds matched to the age groups from CDC data, and coverage levels of 0, 25%, 50%, 75%, and 100%. • The secondary attack rates within households without PEP ar PEP ̅̅̅̅̅̅ = 0.078 and with PEP ar PEP = 0.014 came from the cas/imdev RCT in the low attack rate scenario. 3 The attack rate without PEP in the high attack rate scenario ar PEP ̅̅̅̅̅̅ = 0.211 came from the meta-analysis by Thompson, et al. 4 We calculated the attack rate with PEP in the high attack rate scenario ar PEP = 0.038 by applying the 81% relative risk reduction observed in the cas/imdev RCT. • We calculated hr( , , ) from CDC data. We dropped all cases where age, sex, race/ethnicity, or hospitalization status was unknown. 1 • We calculated hfr( , , ) similarly from CDC data, by dropping all cases which were not hospitalized or where age, sex, race/ethnicity, or mortality status was unknown. • We determined the unit costs mAbs = $2,550 using $2,100 as the cost of the medication based on the federal government purchase price and $450 as the cost of administration based on Centers for Medicare and Medicaid Services reimbursement rates. 5 

CDC Case Surveillance Task Force. COVID-19 Case Surveillance Public Use Data

Subcutaneous REGEN-COV Antibody Combination to Prevent Covid-19

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Setting-specific Transmission Rates: A Systematic Review and Meta-analysis

Regeneron Pharmaceuticals. REGENERON ANNOUNCES NEW U.S. GOVERNMENT AGREEMENT TO PURCHASE ADDITIONAL DOSES OF REGEN-COV TM (CASIRIVIMAB AND IMDEVIMAB) ANTIBODY COCKTAIL

Monoclonal Antibody COVID-19 Infusion

Costs for a hospital stay for COVID-19