J Korean Med Sci.  2022 Jan;37(4):e28. 10.3346/jkms.2022.37.e28.

An Outbreak of Breakthrough Infections by the SARS-CoV-2 Delta Variant in a Psychiatric Closed Ward

• Wi YM
• Kim SH
• Peck KR

• KMID: 2525009
• DOI: http://doi.org/10.3346/jkms.2022.37.e28

Abstract

Background
A rapid decline in immunity and low neutralizing activity against the delta variant in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccinees has been observed. This study describes an outbreak of coronavirus disease 2019 (COVID-19) breakthrough infections caused by the SARS-CoV-2 delta variant in a psychiatric closed ward.
Methods
Data from epidemic intelligence service officers were utilized to obtain information regarding demographic, vaccination history, and clinical data along with SARSCoV-2 PCR test results for a COVID-19 outbreak that occurred in a closed psychiatric ward.
Results
Among the 164 residents, 144 (87.8%) received two doses of vaccines, with 137 (95.1%) receiving two doses of ChAdOx1 nCoV-19 vaccine. The mean interval between the second dose of vaccine and COVID-19 diagnosis was 132.77 ± 40.68 days. At the time of detection of the index case, SARS-CoV-2 had spread throughout the ward, infecting 162 of 164 residents. The case-fatality ratio was lower than that in the previously reported outbreak before vaccines were available (1.2%, 2/162 vs. 6.9%, P = 0.030). Prolonged hospitalization occurred in 17 patients (11.1%) and was less prevalent in the vaccinated group than in the unvaccinated group (8.5% vs. 25.0%, P = 0.040).
Conclusion
The findings of this study highlight that while vaccination can reduce mortality and the duration of hospitalization, it was not sufficient to prevent an outbreak of the SARSCoV-2 delta variant in this psychiatric hospital setting.

Keyword

COVID-19; Breakthrough; SARS-CoV-2 delta Variant; Psychiatric Hospital

Figure

• 

  Fig. 1 An epidemic curve of the COVID-19 patients in a psychiatric hospital. The solid arrows indicate routine testing of PCR, while the empty arrows indicate testing in symptomatic patients. The horizontal axis indicated the date on which the test was performed, while the vertical axis is the number of confirmed patients.COVID-19 = coronavirus disease 2019.

• 

  Fig. 2 Outcomes according to the period from vaccination to COVID-19 diagnosis. The horizontal axis is the period from vaccination to diagnosis of COVID-19, while the vertical axis is the number of vaccinated residents (Total number = 164).COVID-19 = coronavirus disease 2019.

Reference

1. Chau NVV, Ngoc NM, Nguyet LA, Quang VM, Ny NTH, Khoa DB, et al. An observational study of breakthrough SARS-CoV-2 Delta variant infections among vaccinated healthcare workers in Vietnam. EClinicalMedicine. 2021; 41:101143. PMID: 34608454.

2. Burugorri-Pierre C, Lafuente-Lafuente C, Oasi C, Lecorche E, Pariel S, Donadio C, et al. Investigation of an outbreak of COVID-19 in a french nursing home with most residents vaccinated. JAMA Netw Open. 2021; 4(9):e2125294. PMID: 34515786.

3. Bergwerk M, Gonen T, Lustig Y, Amit S, Lipsitch M, Cohen C, et al. Covid-19 breakthrough infections in vaccinated health care workers. N Engl J Med. 2021; 385(16):1474–1484. PMID: 34320281.

4. Jung J, Sung H, Kim SH. Covid-19 breakthrough infections in vaccinated health care workers. N Engl J Med. 2021; 385(17):1629–1630. PMID: 34587378.

5. Aldridge RW, Yavlinsky A, Nguyen V, Eyre MT, Shrotri M, Navaratnam AMD, et al. Waning of SARS-CoV-2 antibodies targeting the Spike protein in individuals post second dose of ChAdOx1 and BNT162b2 COVID-19 vaccines and risk of breakthrough infections: analysis of the Virus Watch community cohort. medRxiv. November 9, 2021. https://www.medrxiv.org/content/10.1101/2021.11.05.21265968v1.

6. Wall EC, Wu M, Harvey R, Kelly G, Warchal S, Sawyer C, et al. Neutralising antibody activity against SARS-CoV-2 VOCs B.1.617.2 and B.1.351 by BNT162b2 vaccination. Lancet. 2021; 397(10292):2331–2333. PMID: 34090624.

7. Zhou D, Dejnirattisai W, Supasa P, Liu C, Mentzer AJ, Ginn HM, et al. Evidence of escape of SARS-CoV-2 variant B.1.351 from natural and vaccine-induced sera. Cell. 2021; 184(9):2348–2361.e6. PMID: 33730597.

8. Chun JY, Jun JY, Choi J, Jo M, Kwak K, Jeong Y, et al. Coronavirus disease 2019 outbreak in a psychiatric closed ward: what we have to learn. Front Psychiatry. 2021; 11:579235. PMID: 33551861.

9. Love J, Keegan LT, Angulo FJ, McLaughlin JM, Shea KM, Swerdlow DL, et al. Continued need for non-pharmaceutical interventions after COVID-19 vaccination in long-term-care facilities. Sci Rep. 2021; 11(1):18093. PMID: 34508133.

10. Hsu ST, Chou LS, Chou FH, Hsieh KY, Chen CL, Lu WC, et al. Challenge and strategies of infection control in psychiatric hospitals during biological disasters-From SARS to COVID-19 in Taiwan. Asian J Psychiatr. 2020; 54:102270. PMID: 32619835.

11. Korea Institute for Healthcare Accreditation. Assessment execution. Updated 2021. Accessed November 28, 2021. https://www.koiha.or.kr/web/en/program/assEnforce.do .

12. Barda N, Dagan N, Cohen C, Hernán MA, Lipsitch M, Kohane IS, et al. Effectiveness of a third dose of the BNT162b2 mRNA COVID-19 vaccine for preventing severe outcomes in Israel: an observational study. Lancet. 2021; 398(10316):2093–2100. PMID: 34756184.