Rapid decrease of nasopharyngeal SARS‐CoV‐2 antigen in an outbreak of the Omicron strain

Nagasawa, Mitsuru; Kato, Tomoyuki; Yamaguchi, Yoshimi; Sugita, Yoshimitsu; Kajiwara, Hideki

doi:10.1002/jmv.28179

Cited by 5 publications

(4 citation statements)

References 3 publications

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“…After the sixth wave, the pneumonia symptoms of COVID-19 tended to be milder than those before [15][16][17][18][19]. Since the eighth wave, the number of beds for critically ill patients has decreased, indicating that fewer COVID-19 patients require hospitalization among healthy individuals.…”

Section: Discussionmentioning

confidence: 99%

Single-Facility Analysis of COVID-19 Status of Healthcare Employee During the Eighth and Ninth Pandemic Waves in Japan After Introducing Regular Rapid Antigen Testing

Nagasawa,

Kato,

Sakaguchi

et al. 2024

Preprint

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Background Community infections of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have increased rapidly since the emergence of the Omicron strain. During the eighth and ninth pandemic waves—when movement restrictions in the community were eased—the all-case registration system was changed, and the actual status of infection became uncertain. Methods We conducted regular rapid antigen tests (R-RAT) once or twice a week to examine the actual state of coronavirus disease (COVID-19) diagnosis among healthcare employees. Results Overall, 320 (1.42/day) and 299 (1.76/day) employees were infected in the eighth and ninth pandemic waves. During both periods, 59/263 doctors (22.4%), 335/806 nurses (41.6%), 92/194 administrative employees (47.4%), and 129/218 clinical laboratory technicians (59.2%) were infected. In the eighth wave, 56 of 195 employees were infected through close contact; in the ninth wave, 26 of 62 employees were infected. No significant difference was observed in the number of vaccinations between infected and non-infected employees. The positivity rate of R-RAT was 0.41% and 0.45% in the eighth and ninth waves. R-RAT detected infection in 212 and 229 employees during the eighth and ninth waves, respectively; the ratio of R-RAT-detected positive employees to those who reported infection was significantly higher during the ninth wave (odds ratio: 1.67, 95% confidence interval: 1.17–2.37, p

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Section: Discussionmentioning

confidence: 99%

Single-Facility Analysis of COVID-19 Status of Healthcare Employee During the Eighth and Ninth Pandemic Waves in Japan After Introducing Regular Rapid Antigen Testing

Nagasawa,

Kato,

Sakaguchi

et al. 2024

Preprint

View full text Add to dashboard Cite

show abstract

“…After the sixth wave, the pneumonia symptoms of COVID-19 tended to be milder than those before [ 15 , 16 , 17 , 18 , 19 ]. Since the eighth wave, the number of beds for critically ill patients decreased, indicating that fewer COVID-19 patients among healthy individuals required hospitalization.…”

Section: Discussionmentioning

confidence: 99%

Single-Facility Analysis of COVID-19 Status of Healthcare Employees during the Eighth and Ninth Pandemic Waves in Japan after Introducing Regular Rapid Antigen Testing

Nagasawa,

Kato,

Sakaguchi

et al. 2024

Vaccines

Self Cite

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Background: Community infections of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have increased rapidly since the emergence of the Omicron strain. During the eighth and ninth pandemic waves—when movement restrictions in the community were eased—the all-case registration system was changed, and the actual status of infection became uncertain. Methods: We conducted regular rapid antigen tests (R-RATs) once or twice a week as self-testing to examine the actual state of coronavirus disease (COVID-19) diagnosis among healthcare employees. Results: Overall, 320 (1.42/day) and 299 (1.76/day) employees were infected in the eighth and ninth pandemic waves. During both periods, 59/263 doctors (22.4%), 335/806 nurses (41.6%), 92/194 administrative employees (47.4%), and 129/218 clinical laboratory technicians (59.2%) were infected. In the eighth wave, 56 of 195 employees were infected through close contact; in the ninth wave, 26 of 62 employees were infected. No significant difference was observed in the number of vaccinations between infected and non-infected employees. The positivity rate of R-RATs was 0.41% and 0.45% in the eighth and ninth waves. R-RATs detected infection in 212 and 229 employees during the eighth and ninth waves, respectively; the ratio of R-RAT-detected positive employees to those who reported infection was significantly higher during the ninth wave (odds ratio: 1.67, 95% confidence interval: 1.17–2.37, p < 0.001). Conclusions: The number of infected healthcare employees remained high during the eighth and ninth pandemic waves in Japan. The R-RAT is considered effective for detecting mild or asymptomatic COVID-19 at an early stage and at a high rate in healthcare employees.

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“…For all the hospitalized patients who did not undergo an FA test, a SARS-CoV-2 quantitative antigen test was performed at admission as part of the infection control strategy of our hospital. The HISCL™ SARS-CoV-2 Ag kit (Sysmex, Kobe, Japan) was used for a quantitative assay for the SARS-CoV-2 antigen [ 19 ] until July 2022 and has been replaced with the Elecsys ® SARS-CoV-2 antigen kit (Roche Diagnostics Japan, Tokyo, Japan) since August 2022. According to an in-house validation study, the two assays had no significant differences in terms of sensitivity and specificity for detecting the SARS-CoV-2 antigen.…”

Section: Methodsmentioning

confidence: 99%

Impact of the Omicron Strain on Febrile Convulsions Requiring Hospitalization in Children: A Single-Center Observational Study

Nagasawa,

Shimoyama,

Hashimoto

et al. 2024

Pediatric Reports

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Background. The emergence of the Omicron strain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at the end of December 2021 has drastically increased the number of infected children in Japan, along with the number of children with febrile convulsions, but its clinical impact is unclear. Materials and Methods. We compared the frequency of SARS-CoV-2 infection in children hospitalized with febrile convulsions with the frequency of SARS-CoV-2 infection in children with fever and respiratory symptoms without convulsions. Results. In 2021 and 2022, 49 and 58 children required emergency hospitalization for febrile convulsions (FC group) with status epilepticus or cluster spasms, in which 24 and 38 children underwent a Filmarray® respiratory panel test (FA test), respectively, and others received a quantitative antigen test for SARS-CoV-2. In 2022, only six patients tested positive for SARS-CoV-2 (10.3%, 6/58). As a reference group, 655 children aged <10 years who underwent the FA test for fever and respiratory symptoms during the same period were investigated, and 4 (1.8%, 4/223) and 42 (9.7%, 42/432) tested positive for SARS-CoV-2 in 2021 and 2022, respectively. Rhinovirus/enterovirus (RV/EV) was the most frequently detected virus (40.3%, 264/655), followed by respiratory syncytial virus (RSV) (18.9%, 124/655) and parainfluenza virus 3 (PIV3) (7.8%, 51/655). There was no significant difference in the trend of detected viruses between the two groups. Conclusions. The frequency and severity of febrile convulsions requiring hospitalization associated with SARS-CoV-2 infection of the Omicron strain may be similar to that of other respiratory viruses in children.

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Rapid decrease of nasopharyngeal SARS‐CoV‐2 antigen in an outbreak of the Omicron strain

Cited by 5 publications

References 3 publications

Single-Facility Analysis of COVID-19 Status of Healthcare Employee During the Eighth and Ninth Pandemic Waves in Japan After Introducing Regular Rapid Antigen Testing

Single-Facility Analysis of COVID-19 Status of Healthcare Employee During the Eighth and Ninth Pandemic Waves in Japan After Introducing Regular Rapid Antigen Testing

Single-Facility Analysis of COVID-19 Status of Healthcare Employees during the Eighth and Ninth Pandemic Waves in Japan after Introducing Regular Rapid Antigen Testing

Impact of the Omicron Strain on Febrile Convulsions Requiring Hospitalization in Children: A Single-Center Observational Study

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