Table 1.

Research on optimization of COVID-19 screening strategy.

Research population	Optimization directions	Testing methods	Strategy	Evaluation index	Study
General population	Screening population	PCRa and RATb	Optimal testing strategy: allocation of PCR and RAT to different age groups and individuals with varying symptoms while ensuring that that all severe patients are tested and total expenditure remains within the budget Risk‐based strategy Symptom‐based strategy Severe‐only strategy Universal random testing strategy	NT-posc, NT-negd, NF-pose, and NF-negf Nmissg Ntest-posh and Pposi	Du et al [20], 2022
General population	Screening population	RAT	Strategy 1: symptomatic testing at health care facilities Strategy 2: asymptomatic testing in the community setting (households, schools, formal workplaces, or religious gather) with different distribution: (1) even distribution to as many entities as possible once per week and (2) concentrated distribution to test all individuals in selected entities twice a week who will continue to get tested throughout the epidemic. With or without quarantine of household members. 85% of weekly tests for strategy 2 and the rest for strategy 1 All weekly tests for strategy 1 Tests are first used for strategy 1, and any remaining tests are used for strategy 2 next week No testing	Proportion of infections averted relative to the no-testing baseline Number of tests available per 100,000 persons per day Number of additional infections averted for every 100 more tests Reduction of days when Rtj>1 Proportion of infections	Han et al [21], 2022
General population	Screening population	PCR	No testing and quarantining Quarantine people in the state “contagious symptomatic” only Symptom-based plus random or greedy sampling and quarantining of positive people Symptom-based plus sampling based on optimization of community graph and population risk factors and quarantining of positive people	Total and peak morbidity Personal and global quarantine efficiency Number of human-days in different states	Berestizshevsky et al [22], 2021
Vaccinated populations	Screening population	PCR and RAT	RAT followed by PCR testing in 100% of the population weekly in the United States and India	Ninfectedk Ncasesl Number of the hospitalized, dead, and recovered Cost	Kumar et al [23], 2022
Travelers	Screening population and screening timing	PCR	PCR testing is not required for travel in all areas PCR testing is required in all regions within 7, 5, and 3 days before travel All those coming from high-risk areas (risk level 3-4) need to be tested within 3 days before travel All those from medium- and high-risk areas (risk level 2-4) need to be tested within 3 days before travel	Ninfected and Ncases Ntestm The medical expenditure	Zhou et al [24], 2021
People at gathering activities	Screening population	PCR	None of the participants are quarantined before the event unless they are contact traced All participants traveling from overseas are quarantined for 14 days before the event All participants are quarantined before the event All mainland participants are tested before the event All participants are tested before the event All participants are tested before the event day 7 following the opening of the event	Ncases Ninfected, and percentage change of new and cumulative infections	Wong et al [25], 2022
General population	Screening population	PCR and RAT	Using PCR to test symptomatic patients in outpatient settings Community-based screening by RAT Symptom-driven outpatient diagnostic testing by RAT	Reduction in cumulative symptomatic incidence Number of unnecessary isolations	Baik et al [26], 2022
Workers	Screening population	PCR	No RT-PCRn testing of all workers Testing the workers with COVID-19-like symptoms in isolation Testing the workers without COVID-19-like symptoms but in household quarantine Testing all staff	Ntest Change of days in quarantine per test Change of workers spreading per test Testing accuracy	Sandmann et al [27], 2020
College students	Screening population	PCR	Testing the students with COVID-19-like symptoms RT-PCR testing for symptomatic students Testing for all students Testing for all students+retesting symptomatic students with a negative first test Testing for all students+retesting all students with a negative first test.	NT-pos and NT-neg Ntest and Ntest per person	Van Pelt et al [29], 2021
Travelers	Screening timing	PCR	No measures PCR testing of passengers before embarkation and social isolation PCR testing of passengers before embarkation, daily testing on board, and social isolation	Ncases	Chowell et al [32], 2021
School students	Screening population	PCR and RAT	Testing based on symptoms and quarantine for 7 days Reactive quarantine of the class level or specialization Reactive screening of the entire class on the day after detection of the case by symptom-based testing, and a screening on days 4 or 7 after case identification Regular testing of the entire school once every 2 weeks or once or twice a week Regular testing with different levels of adherence among the nonvaccinated and reactive closure of the class when every case is detected	Rt The proportion of cases reduction Ncases Student days lost	Colosi et al [31], 2022
School students	Screening population and screening timing	RAT	Isolation of year group bubbles for 10 days Twice weekly mass testing and isolation of year group bubbles for 10 days Tested daily by RATs for 7 days from the day after identification of every case Twice weekly mass testing and tested daily by RATs for 7 days from the day after identification of every case Twice weekly mass testing No testing or isolation	School days miss per person Ninfected Asymptomatic cases Ntest per person Prevalence Absent persons	Leng et al [30], 2022
Health care workers in the nursing home	Screening population	RAT	Testing the health care person within the facility when there are ≥1 positive cases Testing all asymptomatic health care persons in the absence of a known outbreak at predetermined intervals from 1 day to 7 days	Maximum preventable transmission	Zipfel et al [28], 2022
Travelers	Screening timing	PCR and RAT	Testing and quarantine strategies for fully vaccinated travelers and unvaccinated travelers A negative preboarding A negative preboarding test and a negative arrival test Negative preboarding, arrival, and quarantine exit tests 14 days quarantine	Rt Adjusted breakthrough IRo Expected number of subsequent infections	Lee et al [37], 2022
Travelers	Screening timing	PCR and RAT	Isolate individuals before or during travel when symptoms appear Test 3 days before travel Test on the day of travel Test 1 day before arrival Test 3 days before arrival The best time to conduct a second test after travel in the absence of postentry quarantine Monitor and isolate symptoms before, during, and after travel 14-day, 10-day, and 7-day isolation	The proportional reduction in transmission risk	Johansson et al [33], 2021
Travelers	Screening timing	PCR, RAT	Predeparture testing No test PCR test 3 days before departure (on day 3) RAT test 1 day before departure (on day 1) Postarrival restrictions Unlimited PCR on days 0 and 4 Daily RAT for 5 days Self-isolation for 5 days with PCR test on days 0 and 4 Self-isolation for 5 days and daily RAT test Government-managed isolation for 7 days and quarantine with PCR test on day 5 Government-managed isolation for 14 days and quarantine with PCR test on days 3 and 12	Rt/R0p The proportion of infected traveler causes, the number of infected travelers that reaches 50 cases from 1 traveler	Steyn et al [34], 2022
Travelers	Screening timing	PCR and RAT	Anterior nose PCR testing within 3 days before departure PCR test within 3 days of departure, on the fifth day after arrival, and isolation for 5 days after arrival RAT within 3 days of departure and on the fifth day after arrival RAT on the day of departure, PCR test on day 5 after arrival, and isolation for 5 days after arrival PCR test on arrival for 5 days	Cumulative infectious days Ninfected The ratio of NF-pos to NT-pos	Kiang et al [35], 2021
Travelers	Screening timing	PCR	RT-PCR tests on arrival and quarantine for 5 days and a second PCR test at the end of quarantine RT-PCR tests on arrival and quarantine for 5 days Quarantine for 14 days without test	IR and proportions of asymptomatic or presymptomatic cases Nmiss Cumulative probability and hazard rate of developing symptoms	Jen et al [36], 2022
Travelers	Screening timing and screening frequency	PCR and RAT	Isolation only Pretest and inbound testing and isolation Pretest, inbound testing, and outbound isolation and testing Pretest, inbound testing and isolation, and daily testing until the exit Pretest, inbound testing and isolation, and testing every 2 days Pretest, inbound testing and isolation, and testing every 3 days Pretesting, inbound testing, RAT every 3 days, and outbound PCR Pretesting, inbound testing, isolation, and alternative testing at exit (a PCR test or a RAT)	Nmiss	Dickens et al [38], 2021
Contacts	Screening frequency	RAT	Isolation-based strategies: isolation duration of 0, 3, 5, 7, 10, and 14 days after exposure to the case; no testing during isolation or testing on the last day of the isolation period Daily testing strategy: daily RAT of exposed individuals for 1, 3, 5, 7, 10, or 14 days, with no isolation required unless symptomatic or positive testing occurs	Onward transmission potential from secondary cases	Quilty et al [39], 2021
Travelers	Screening timing	PCR	Isolation and no testing Test at the beginning of isolation Test at the end of isolation Test at the beginning and end of isolation Test during the isolating period.	PQTRq	Wells et al [40], 2020
Contacts	Screening timing	PCR and RAT	RAT at 2 best times (day 1 and day 3) RAT at 3 best times (day 1 and day 3) and an additional test (PCR or RAT)	The expected number of infection days	Foncea et al [41], 2022
Infected people	Screening timing	PCR and RAT	A RT-PCR test administered 1 or 2 days before the end of quarantine Two RT-PCR tests administered on days 6 or 7 and then on day 8 A 6-day quarantine with tests on days 4, 5, and 6 using a highly sensitive RT-PCR test in cases where the shortest quarantine is needed A RAT with test administered on day 9 or 10 A 9-day quarantine with tests on days 7 and 8	PQTR	Peng et al [42], 2021
General population	Screening frequency	PCR	Citizens, family members, and recent contacts who test positive in the first round of PCR and those who do not participate must be quarantined for 10 days All regions with a positivity rate of ≥0.7% in the first round of testing should undergo a second round of mass testing	The 7-day rolling average of new infections and Rt	Kahanec et al [43], 2021
General population	Screening frequency	PCR	Community transmission: 2 tests per 1000 people (low incidence) Outbreak response: 4 tests per 1000 people (higher incidence)	Ntest The percentage of positive tests and the percentage of transmission reduction	Baker et al [45], 2021
Migrant workers	Screening frequency	PCR, RAT	A PCR test every 2 weeks Weekly RAT	Rt Ninfected	Koo et al [46], 2022
General population	Screening frequency	RAT	Mass testing with a frequency of fortnightly, weekly, or tridaily testing begins on the 30th day Mass testing with a frequency of fortnightly, weekly, or tridaily testing begins on the peak of the outbreak	Ninfected, Ncases, and cases of intensive care unit Rt	Koo et al [44], 2022

^aPCR: polymerase chain reaction.

^bRAT: rapid antigen test.

^cN_T-pos: number of true-positive results.

^dN_T-neg: number of true-negative results.

^eN_F-pos: number of false-positive results.

^fN_F-neg: number of false-negative results.

^gN_miss: number of missed infections.

^hN_test-pos: number of people who test positive.

ⁱP_pos: proportion of positive results.

^jR_t: effective reproduction number (positives to true positives transmission potential from secondary cases).

^kN_infected: number of infected people.

^lN_cases: number of confirmed cases.

^mN_test: number of tests.

ⁿRT-PCR: reverse transcription-polymerase chain reaction.

^oIR: infection rate.

^pR₀: basic reproductive number.

^qPQTR: postquarantine transmission risk.