Nunes Marta C, Mbotwe-Sibanda Sthembile, Baillie Vicky L, Kwatra Gaurav, Aguas Ricardo, Madhi Shabir A
South African Medical Research Council, Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 1862, South Africa.
Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 1862, South Africa.
Vaccines (Basel). 2022 Mar 17;10(3):459. doi: 10.3390/vaccines10030459.
We investigated Omicron infections among healthcare workers (HCW) presenting with symptoms of SARS-CoV-2 infection and evaluated the protective effect of vaccination or prior infection. Between 24 November and 31 December 2021, HCW in Johannesburg, South Africa, were tested for SARS-CoV-2 infection by Nucleic Acid Amplification Test (NAAT). Blood samples collected either at the symptomatic visit or in the 3 months prior, were tested for spike protein immunoglobulin G (IgG). Overall, 433 symptomatic HCW were included in the analysis, with 190 (43.9%) having an Omicron infection; 69 (16.7%) were unvaccinated and 270 (62.4%) received a single dose of the Ad26.COV.2 vaccine. There was no difference in the odds of identifying Omicron between unvaccinated and Ad26.COV.2 vaccinated HCW (adjusted odds ratio (aOR) 0.81, 95% confidence interval (CI): 0.46, 1.43). One-hundred and fifty-four (35.3%) HCW had at least one SARS-CoV-2 NAAT-confirmed prior infection; these had lower odds of Omicron infection compared with those without past infection (aOR 0.55, 95%CI: 0.36, 0.84). Anti-spike IgG concentration of 1549 binding antibody unit/mL was suggestive of significant reduction in the risk of symptomatic Omicron infection. We found high reinfection and vaccine breakthrough infection rates with the Omicron variant among HCW. Prior infection and high anti-spike IgG concentration were protective against Omicron infection.
我们调查了出现SARS-CoV-2感染症状的医护人员（HCW）中的奥密克戎感染情况，并评估了疫苗接种或既往感染的保护作用。2021年11月24日至12月31日期间，南非约翰内斯堡的医护人员通过核酸扩增检测（NAAT）进行了SARS-CoV-2感染检测。在出现症状就诊时或之前3个月采集的血液样本，检测了刺突蛋白免疫球蛋白G（IgG）。总体而言，433名有症状的医护人员纳入分析，其中190人（43.9%）感染了奥密克戎；69人（16.7%）未接种疫苗，270人（62.4%）接种了单剂Ad26.COV.2疫苗。未接种疫苗和接种Ad26.COV.2疫苗的医护人员中，检测出奥密克戎的几率没有差异（调整后的优势比（aOR）为0.81，95%置信区间（CI）：0.46，1.43）。154名（35.3%）医护人员至少有一次经SARS-CoV-2核酸扩增检测确诊的既往感染；与未感染过的医护人员相比，这些人感染奥密克戎的几率较低（aOR 0.55，95%CI：0.36，0.84）。抗刺突IgG浓度为1549结合抗体单位/毫升提示有症状的奥密克戎感染风险显著降低。我们发现医护人员中奥密克戎变异株的再感染率和疫苗突破性感染率很高。既往感染和高抗刺突IgG浓度对奥密克戎感染有保护作用。
