Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Sep-Oct:43:102127.
doi: 10.1016/j.tmaid.2021.102127. Epub 2021 Jun 23.

Logistic advantage of two-step screening strategy for SARS-CoV-2 at airport quarantine

Isao Yokota  1 , Peter Y Shane  2 , Takanori Teshima  3
Affiliations

Logistic advantage of two-step screening strategy for SARS-CoV-2 at airport quarantine

Isao Yokota et al. Travel Med Infect Dis. 2021 Sep-Oct.

Abstract

Background: Airport quarantine is required to reduce the risk of entry of travelers infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, it is challenging for both high accuracy and rapid turn-around time to coexist in testing; polymerase chain reaction (PCR) is time-consuming with high accuracy, while antigen testing is rapid with less accuracy. However, there are few data on the concordance between PCR and antigen testing.

Methods: Arrivals at three international airports in Japan between July 29 and September 30, 2020 were tested for SARS-CoV-2 using self-collected saliva by a screening strategy with initial chemiluminescent enzyme immunoassay (CLEIA) followed by confirmatory nucleic acid amplification tests (NAAT) only for intermediate range antigen concentrations.

Results: Among the 95,457 persons entering Japan during the period, 88,924 (93.2%) were tested by CLEIA, and 0.29% (254/88,924) were found to be SARS-CoV-2 antigen positive (≥4.0 pg/mL). NAAT was required for confirmatory testing in 0.58% (513/88,924) with intermediate antigen concentrations (0.67-4.0 pg/mL) whereby the virus was detected in 6.6% (34/513). This two-step strategy reduced the utilization of NAAT to one out of every 173 test subjects. The estimated performance of this strategy did not show significant increase in false negatives as compared to performing NAAT in all subjects.

Conclusions: Point of care testing by quantitative CLEIA using self-collected saliva is less labor-intensive and yields results rapidly, thus suitable as an initial screening test. Reserving NAAT for CLEIA indeterminate cases may prevent compromising accuracy while significantly improving the logistics of administering mass-screening at large venues.

Keywords: CLEIA; COVID-19; PCR; Quarantine; SARS-CoV-2.

PubMed Disclaimer

Conflict of interest statement

IY reports a policy research grant from the Ministry of Health, Labour and Welfare, Japan, during the conduct of the study; and personal fees from Chugai Pharmaceutical, AstraZeneca, Japan Tobacco Pharmaceutical Division, and Nippon Shinyaku, outside the submitted work. PYS reports personal fees from AYUMI Pharmaceutical, Japan Pharmaceutical Manufacturers Association, Alexion Pharmaceuticals, and Kyowa Kirin, outside the submitted work. TT reports policy research grant from the Ministry of Health, Labour and Welfare, Japan, during the conduct of the study; personal fees from Merck Sharp & Dohme, Takeda Pharmaceutical, Pfizer Japan, and Bristol Myers Squibb, grants and personal fees from Kyowa Hakko Kirin, grants, personal fees, and non-financial support from Novartis Pharma, grants from Chugai Pharmaceutical, Sanofi, Astellas Pharma, Teijin Pharma, Fuji Pharma, Nippon Shinyaku, the Japan Society for the Promotion of Science (Grants-in-Aid for Scientific Research), and the Center of Innovation Program of the Japan Science and Technology Agency, and non-financial support from Janssen Pharmaceutical, outside the submitted work.

Figures

Fig. 1
Fig. 1
Flow chart of mass screening of international arrivals by the two-step strategy 88,924 arrivals at international airports were screened using self-collected saliva. Initial CLEIA results were positive in 254 (0.28%) and negative in 88,157 (99.14%) persons. Confirmatory NAAT was only performed for samples in the indeterminate range (n = 513; 0.58%).
Fig. 2
Fig. 2
Barplots of viral antigen concentrations (a) The frequency of viral antigen concentrations of the entire test population sorted by final diagnosis by the two-step strategy (288 positives and 88,636 negatives). (b) The frequency of antigen concentration in 513 persons judged to be indeterminate by initial CLEIA. NAAT was only performed for CLEIA results with antigen concentrations between 0.67 and 4.0 pg/mL. The frequency of NAAT negative samples consistently approach zero with increasing antigen concentrations, while NAAT positives did not show any trend.
See this image and copyright information in PMC

References

    1. Ma Honein, Christie A., Rose D.A., et al. Summary of guidance for public health strategies to address high levels of community transmission of sars-cov-2 and related deaths, december 2020. MMWR Morb Mortal Wkly Rep. 2020;69(49):1860–1867. - PMC - PubMed
    1. Wu J.T., Leung K., Leung G.M. Nowcasting and forecasting the potential domestic and international spread of the 2019-ncov outbreak originating in wuhan, China: a modelling study. Lancet. 2020;395(10225):689–697. - PMC - PubMed
    1. Chinazzi M., Davis J.T., Ajelli M., et al. The effect of travel restrictions on the spread of the 2019 novel coronavirus (covid-19) outbreak. Science. 2020;368(6489):395–400. - PMC - PubMed
    1. Liu J.Y., Chen T.J., Hwang S.J. Analysis of imported cases of covid-19 in taiwan: a nationwide study. Int J Environ Res Publ Health. 2020;17(9):3311. - PMC - PubMed
    1. Dickens B.L., Koo J.R., Lim J.T., et al. Strategies at points of entry to reduce importation risk of covid-19 cases and re-open travel. J Trav Med. 2020;27(8):taaa141. - PMC - PubMed