Put up-exposure prophylaxis with monoclonal antibodies might cut back well being system burden within the US

In a study conducted at the University of Washington, USA, researchers claim that post-exposure prophylaxis with monoclonal antibodies could improve clinical outcomes and health system costs for coronavirus disease (COVID-19). The study is currently available on the medRxiv * preprint server.

background

The greatest impact of the COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was observed in the United States, with more than 39.9 million infections and over 648,000 deaths. Despite sufficient vaccine availability and massive vaccination efforts, the number of new infections in the country is steadily increasing, most likely due to new virus variants with higher immunogenicity, vaccination delay and declining immunity.

In addition to vaccines, monoclonal antibody (mAb) therapies have been shown to be effective in preventing infection in unvaccinated people at high risk of exposure to someone with SARS-CoV-2 infection. Unlike vaccines, which induce host cell immunity to eliminate the virus, monoclonal antibodies bind directly to the viral antigen, resulting in faster removal of the virus from the system. This makes monoclonal antibody therapy an attractive prophylaxis to prevent the transmission of SARS-CoV-2 in the household. However, high production costs sometimes limit the large-scale application of antibody-based therapies.

In the current study, scientists evaluated the health benefits and costs of monoclonal antibodies as post-exposure prophylaxis.

Study design

Scientists gathered information on antibody efficacy from the placebo-controlled, randomized, household phase 3 study of the monoclonal antibody cocktail casirivimab and imdevimab. In the study, the antibody cocktail was injected subcutaneously into asymptomatic, SARS-CoV-2 negative household members of people with confirmed COVID-19. According to the study results, therapy with monoclonal antibodies reduces the risk of symptomatic COVID-19 by 81%.

From the study results, the scientists estimated a secondary infection rate of 7.8%. They used a decision analytics model to combine the study results with population data on the demographic details of households, number of COVID-19 cases and demographics, and vaccine coverage to get the number of symptomatic COVID-19 cases, hospital stays, mortality and the cost of antibody therapy in the health system.

Important observations

Approximately 753 participants were treated with the antibody cocktail in the study, and 752 participants were in the placebo group. The scientists combined the results with COVID-19 case data from 154,136 people, vaccination data from 1,888 people, and household demographic data from 3,190,040 people in 1,394,399 households. Based on the ethnic characteristics of the household members, they estimated that approximately 17%, 20%, 53%, and 11% of unvaccinated household contacts are non-Hispanic Black, Hispanic, non-Hispanic White, and other non-Hispanic ethnic groups. respectively.

The number of averted COVID-19 deaths increases when the minimum age limit for PEP treatment is lowered, and the additional costs (including the cost of PEP with mAbs plus the cost of COVID-19 hospitalization) show the trade-off between lowering the cost of hospitalization and Increase in PEP costs, with a maximum reduction in additional costs for a program offering PEP to people aged 50 and over.

Health Effects of Antibody Therapy

The scientists assumed a situation in which 50% of the unvaccinated contacts aged 50 and over received antibody therapy. This corresponded to 28,187 people with antibody treatment. The health impact analysis found that antibody cocktail treatment coverage of 50% resulted in the prevention of 1,813 symptomatic illnesses, 526 hospitalizations, and 83 deaths.

They expanded the analysis to include household contacts aged 20 and over, and estimated that antibody therapy could prevent more than 5,000 symptomatic COVID-19, 768 hospital admissions and 93 deaths. In contrast, the analysis for household contacts aged 80 and over led to a reduction of 104 symptomatic illnesses, 67 hospital stays and 24 deaths. Notably, a corresponding reduction of 50% was observed in all clinical results tested by increasing the therapy coverage to 75%.

Differences in the health effects of antibody therapy were observed between ethnic groups, with non-Hispanic blacks showing the greatest benefit and non-Hispanic whites showing the least benefit.

Economy of Antibody Therapy

Scientists estimated that without antibody therapy, the cost of hospitalization for secondary SARS-CoV-2 infection acquired through household transmission would be $ 150 million. Another analysis found that this cost could be reduced to $ 147 million by giving 50% of unvaccinated household contacts aged 50 or ≥ 80 years of age antibody therapy. In contrast, they estimated the total health care system cost to include household contacts aged 20 or older for antibody therapy, which is $ 43 million higher than without antibody therapy.

Study significance

The study results show that the clinical outcomes of COVID-19 as well as treatment costs could be improved by introducing monoclonal antibody therapies as post-exposure prophylaxis.

*Important NOTE

medRxiv publishes preliminary scientific reports that are not peer-reviewed and therefore are not considered conclusive, guide clinical practice / health-related behavior, or should be treated as established information.