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COVID-19 testing protocols to guide duration of isolation: a cost-effectiveness analysis
1Philip R. Lee Institute for Health Policy Studies, University of California San Francisco, 490 Illinois St, Box 0936, 95158, San Francisco, CA, USA. Sigal.Maya@ucsf.edu.
Background:
The Omicron variant of SARS-CoV-2 led to a steep rise in transmissions, and emerging variants continue to influence case rates across the US. As public tolerance for isolation abated, CDC guidance on duration of at-home isolation of COVID-19 cases was shortened to five days if no symptoms, with no laboratory test requirement, despite more cautious approaches advocated by other federal experts.
Methods:
We conducted a decision tree analysis of alternative protocols for ending COVID-19 isolation, estimating net costs (direct and productivity), secondary infections, and incremental cost-effectiveness ratios. Sensitivity analyses assessed the impact of input uncertainty.
Results:
Per 100 individuals, five-day isolation had 23 predicted secondary infections and a net cost of $33,000. Symptom check on day five (CDC guidance) yielded a 23% decrease in secondary infections (to 17.8), with a net cost of $45,000. Antigen testing on day six yielded 2.9 secondary infections and $63,000 in net costs. This protocol, compared to the next best protocol of antigen testing on day five of a maximum eight-day isolation, cost an additional $1,300 per secondary infection averted. Antigen or polymerase chain reaction testing on day five were dominated (more expensive and less effective) versus antigen testing on day six. Results were qualitatively robust to uncertainty in key inputs.
Conclusions:
A six-day isolation with antigen testing to confirm the absence of contagious virus appears the most effective and cost-effective de-isolation protocol to shorten at-home isolation of individuals with COVID-19.
Insights
A six-day COVID-19 isolation period with antigen testing is the most effective strategy to reduce secondary infections and costs. This approach balances public health needs with economic considerations for ending at-home isolation.
Area of Science:
- Epidemiology
- Public Health Policy
- Health Economics
Background:
- The emergence of SARS-CoV-2 variants, including Omicron, has driven significant transmission waves across the US.
- Public willingness to adhere to prolonged isolation decreased, prompting revised guidance.
- The Centers for Disease Control and Prevention (CDC) shortened COVID-19 isolation to five days without mandatory testing, diverging from some expert recommendations.
Purpose of the Study:
- To analyze the cost-effectiveness of various COVID-19 at-home isolation protocols.
- To compare secondary infection rates and economic impacts of different de-isolation strategies.
- To identify optimal protocols for ending isolation based on scientific and economic data.
Main Methods:
- Decision tree analysis was employed to model alternative COVID-19 isolation protocols.
- Net costs, including direct expenses and productivity losses, were estimated.
- Secondary infections and incremental cost-effectiveness ratios (ICERs) were calculated, with sensitivity analyses performed.
Main Results:
- A five-day isolation resulted in 23 secondary infections per 100 individuals at a cost of $33,000.
- Symptom-based, five-day isolation (CDC guidance) reduced infections to 17.8 but increased costs to $45,000.
- A six-day isolation with antigen testing yielded only 2.9 secondary infections at a cost of $63,000, proving highly effective.
Conclusions:
- A six-day isolation period incorporating antigen testing to confirm non-contagiousness is the most effective and cost-efficient de-isolation strategy.
- This protocol offers a significant reduction in secondary infections compared to shorter, symptom-based approaches.
- The findings support a data-driven approach to optimizing COVID-19 isolation guidelines.
