SARS-CoV-2 surveillance to be expanded to prevent epidemics

COVID-19 testing strategies should be expanded significantly to include more frequent, faster testing and isolation strategies for people who test positive. These results of a multiscale model study were published in the Lancet Public Health.

Using data on household-specific and age-stratified SARS-CoV-2 transmission data, researchers at the University of Texas at Austin simulated epidemic outbreaks for 150 days. The researchers tested people for COVID-19 at different frequencies (every 1, 7, 14 or 28 days) with 1- or 2-week isolation periods, and rated the Prevention of Years of Life Lost (YLL) and cost effectiveness based on the transmission rate (Re) .

The researchers found that there was an optimal strategy for each Re value in incremental increments, provided that each test costs $ 5 and societal willingness to pay $ 100,000 for each YLL averted.

For low infection rates (Re, 1.1, or 1.2), tests should be done every 28 days and positive individuals should isolate for 1 week. The test should have an additional cost of $ 75 and $ 125, respectively.

If Re increased to 1.3 or 1.4, tests should be run every 14 days at an additional cost of $ 175 and $ 350, respectively. The test frequency should shift to every 7 days when Re is between 1.5 and 1.8. At this point, the additional cost of testing increases to $ 475.

With a Re of 1.9, the isolation time should be increased to 2 weeks for positive persons and remain at 2 weeks for all scenarios with high infection. With a Re of 2.5, the test frequency should be done every day.

The most contagious scenario was a Re of 3.0. It has been found that the optimal strategy in this situation is to include daily testing at an additional cost of $ 275 and a two-week isolation requirement.

The estimated probability of error for these models peaked when Re is 1.5 (error 0.72) and is minimized when Re is 3.0 (error 0.18).

This study was limited by the assumption that infected individuals could not be re-infected. Beyond the 5 month projection of this study, there remains great uncertainty as to whether or not immunity to infection will persist. Unless immunity lasts long, these estimates would be inaccurate.

These projected models indicated that SARS-CoV-2 surveillance programs should be expanded significantly for long-term cost efficiency and to reduce YLL.

Disclosure: Several authors have declared their affiliations with the industry. For a full list of details, see the original article.


Du Z., Pandey A., Bai Y. et al. Comparative cost effectiveness of SARS-CoV-2 test strategies in the US: a model study. Lancet Public Health. 2021; 6 (3): e184-e191. doi: 10.1016 / S2468-2667 (21) 00002-5.

This article originally appeared on Infectious Disease Advisor

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