Low-cost, Repeat COVID-19 Testing Would Decrease Cases, Hospitalizations and Deaths
Key findings
- This computer modeling study projected the impact of four COVID-19 polymerase chain reaction testing strategies in Massachusetts from May 1 to November 1, 2020, under slowing, intermediate and surging epidemic growth scenarios
- Expanding testing beyond hospitalized patients reduced infections, hospitalizations and mortality across all scenarios
- In all scenarios, testing hospitalized and symptomatic patients, plus testing asymptomatic patients one time and retesting if results were negative, led to the most favorable clinical outcomes
- All expanded testing strategies led to reductions in key hospital resource use compared with testing only hospitalized patients
- In all scenarios, testing both symptomatic and hospitalized patients led to lower total costs than testing hospitalized patients alone
To date, the federal government has not developed a national testing strategy for COVID-19. Yet projections based on test results are essential to planning utilization of limited resources, such as hospital beds.
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Pooyan Kazemian, PhD, formerly a research scientist in the Division of General Internal Medicine, and Andrea L. Ciaranello, MD, MPH, and Anne M. Neilan, MD, MPH, infectious disease specialists working in the Medical Practice Evaluation Center at Massachusetts General Hospital, and colleagues used computer modeling to examine the impact of various COVID-19 testing strategies in Massachusetts. Among their findings, reported in Clinical Infectious Diseases, was that expanding reverse transcription polymerase chain reaction (PCR) testing to asymptomatic people would decrease infections, deaths and hospitalizations.
Study Methods
New COVID-19 infections in Massachusetts peaked in late April 2020. The researchers projected what the epidemic would be in Massachusetts from May 1 to November 1, 2020, under three growth scenarios:
- Slowing—same growth as in May, after Massachusetts announced a stay-at-home advisory and non-essential businesses closed
- Intermediate—modest increase in epidemic growth
- Surging—case numbers similar to those in late March/early April in Massachusetts
The team modeled four PCR testing strategies for all 6.9 million state residents (excluding those in long-term care facilities):
- Testing only hospitalized patients (the "Hospitalized" strategy)
- Strategy (a) plus testing of people with any COVID-19–consistent symptoms, who isolated if results were positive ("Symptomatic")
- Strategy (b) plus one-time testing of the entire population ("Symptomatic+asymptomatic–once")
- Strategy (c) plus retesting every 30 days of those who tested negative and remained asymptomatic ("Symptomatic+asymptomatic–monthly")
The article describes the model's structure, inputs and key assumptions in detail.
Clinical Outcomes
- In all epidemic growth scenarios, the expanded testing strategies reduced infections and deaths compared with Hospitalized
- In all scenarios, Symptomatic+asymptomatic–monthly led to the fewest infections, hospitalizations and deaths
Resource Utilization and Costs
In all scenarios, Symptomatic led to lower total costs than Hospitalized (test kits, bed use and lost productivity from being hospitalized or isolating).
Cost-effectiveness
- Under all scenarios, Symptomatic was cost-saving compared with Hospitalized
- Symptomatic+asymptomatic–monthly was more cost-effective than Symptomatic in the surging scenario
- Under surge or near-surge conditions, screening the entire population only one time was an inefficient strategy unless there was repeat screening for people testing negative
- In all scenarios, it was cost-effective or cost-saving to offer repeat testing as long as it cost $5 per test or less
Conclusions
The variable clinical sensitivity of PCR testing for COVID-19 would not be an issue if tests could be low-cost and frequent. Expanded testing can be expected to reduce infections by increasing the isolation of infectious people, thereby reducing hospitalizations and deaths.
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