SARS-CoV-2 RT-PCR positivity of individuals subsequent to completing quarantine upon entry into a country during a transmission-free period
Issued Date
2022-03-01
Resource Type
ISSN
14778939
eISSN
18730442
Scopus ID
2-s2.0-85124079615
Pubmed ID
35123068
Journal Title
Travel Medicine and Infectious Disease
Volume
46
Rights Holder(s)
SCOPUS
Bibliographic Citation
Travel Medicine and Infectious Disease Vol.46 (2022)
Suggested Citation
Srichatrapimuk S. SARS-CoV-2 RT-PCR positivity of individuals subsequent to completing quarantine upon entry into a country during a transmission-free period. Travel Medicine and Infectious Disease Vol.46 (2022). doi:10.1016/j.tmaid.2022.102271 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/87365
Title
SARS-CoV-2 RT-PCR positivity of individuals subsequent to completing quarantine upon entry into a country during a transmission-free period
Author(s)
Other Contributor(s)
Abstract
Background: During the current coronavirus disease 2019 (COVID-19) pandemic, many countries require travellers to undergo a reverse transcription-polymerase chain reaction (RT-PCR) testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) before travelling across borders. However, in persons having recovered from COVID-19, RT-PCR positivity can persist for an extended period. Materials and methods: We describe three cases who sought fit-to-fly certificates in Thailand during the period free of local transmission but were tested positive for RT-PCR for SARS-CoV-2. All had returned from a country with an active outbreak of COVID-19. Their clinical courses are described; positive nasopharyngeal swab samples were processed for viral isolation and whole-genome sequencing (WGS); and serology as well as neutralizing antibody were assessed. The contact tracing was carried out for determining evidence of indigenous transmission among close contacts of those three cases. Results: All three cases were completely asymptomatic. Chest computerized tomography was not compatible with COVID-19 pneumonia; cell cultures failed to rescue replication-competent virus; WGS revealed fragmented viral genetic material from nasopharyngeal swab samples; and serological tests demonstrated stable levels of antibodies, together with the presence of neutralizing antibody, suggesting past infection with negligible transmission risk. Contact tracing identified no transmission in high-risk close contact individuals. Conclusion: RT-PCR positivity for SARS-CoV-2 might detect fragmented viral genome. Issuance of a travel certificate in these circumstances is problematic. Serology tests can help to define past infection. A practical acceptable set of guidelines for issuance of a COVID-19 safety travel certification is a necessity.