Work

Three Cases of COVID-19 Variant Delta With and Without Vaccination — Chengdu City, Sichuan Province, April–May, 2021

Year: 2021

Type: article

Abstract: On April 26, 2021, a 33-year-old male Chinese sailor returning from India via Kathmandu, Nepal, tested positive for the coronavirus disease 2019 (COVID-19) by Chengdu Customs and was confirmed positive by Chengdu CDC (Case A).On May 2, 2021, a housewife in the same flight tested positive for COVID-19 by Pengzhou CDC in Sichuan Province during her quarantine period and was confirmed positive by Chengdu CDC the next day (Case B).On May 9, 2021, a male worker at a cement company in a different flight tested positive for COVID-19 by a third-party testing laboratory during his quarantined period and was confirmed positive by Chengdu CDC the next day (Case C).Epidemiological investigations revealed that Case A arrived in Kathmandu on April 19 from New Delhi, India and Case B arrived in Kathmandu on April 21 from Uttar Pradesh, India.Case C had been working in Kathmandu before returning.They all tested negative for polymerase chain reaction (PCR) tests and antibody tests of COVID-19 before boarding.Case A had been fully vaccinated with two doses of inactivated COVID-19 vaccine (Beijing Institute of Biological Products Co. LTD) with the first dose on January 25 and the second on February 8, 2021.In addition, Case C was vaccinated (Sinovac Biotech Co. LTD) on October 19 and November 4, 2020.Case B was not vaccinated.The samples of nasopharyngeal swabs from the three cases were sequenced by Illumina MiniSeq Sequencing platform with commercial kits on April 27 and May 11, then the whole genome sequences of 29,858, 29,732, and 29,877 bp by length with depth over 3000X were obtained.Compared to the Wuhan reference sequence (MN908947) (1-2), they shared 20 nucleotide variation sites containing the characteristic spike mutations of T19R, L452R, T478K, D614G, China CDC Weekly 544 CCDC Weekly / Vol. 3 / No. 25 Chinese Center for Disease Control and Prevention

Source: China CDC Weekly

DOI: 10.46234/ccdcw2021.137