Risk of COVID-19 and major adverse clinical outcomes among people with disabilities in South Korea

BackgroundEvidence regarding the risk of coronavirus disease (COVID-19) and the major adverse clinical outcomes of COVID-19 among people with disabilities (PwDs) is scarce.ObjectiveThis study investigated the association of disability status with the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) test positivity and the risk of major adverse clinical outcomes among participants who tested positive for SARS-CoV-2.MethodsThis study included all patients (n = 8070) who tested positive for SARS-CoV-2 and individuals without COVID-19 (n = 121,050) in South Korea from January 1 to May 30, 2020. The study variables included officially registered disability status from the government, SARS-CoV-2 test positivity, and major adverse clinical outcomes of COVID-19 (admission to the intensive care unit, invasive ventilation, or death).ResultsThe study participants included 129,120 individuals (including 7261 PwDs), of whom 8070 (6.3%) tested positive for SARS-CoV-2. After adjusting for potential confounding factors, PwDs had an increased risk of SARS-CoV-2 test positivity compared with people without disabilities (odds ratio [OR]: 1.36, 95% confidence interval [CI]: 1.24–1.48). Among participants who tested positive for SARS-CoV-2, PwDs were associated with an increased risk of major adverse clinical outcomes from COVID-19 compared to those without disabilities (OR: 1.43, 95% CI: 1.11–1.86).ConclusionsPwDs had an increased risk of COVID-19 and major adverse clinical outcomes of COVID-19 compared with people without disabilities. Given the higher vulnerability of PwDs to COVID-19, tailored policy and management to protect against the risk of COVID-19 are required.     

Universal Admission Screening for SARS-CoV-2 Infections among Hospitalized Patients,Switzerland, 2020

Switzerland began a national lockdown on March 16, 2020, in response to the rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We assessed the prevalence of SARS-CoV-2 infection among patients admitted to 4 hospitals in the canton of Zurich, Switzerland, in April 2020. These 4 acute care hospitals screened 2,807 patients, including 2,278 (81.2%) who did not have symptoms of coronavirus disease (COVID-19). Overall, 529 (18.8%) persons had >1 symptom of COVID-19, of whom 60 (11.3%) tested positive for SARS-CoV-2. Eight asymptomatic persons (0.4%) also tested positive for SARS-CoV-2. Our findings indicate that screening on the basis of COVID-19 symptoms, regardless of clinical suspicion, can identify most SARS-CoV-2–positive persons in a low-prevalence setting.     

Disparities in Seroprevalence of SARS-CoV-2 Immunoglobulin Antibodies in a Large Midwestern Health Care System

ObjectivesIncreased exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as a result of having an essential job is compounded by factors such as age, race, and ethnicity. We used a cross-sectional study design to describe disparities in the seroprevalence of SARS-CoV-2 immunoglobulin G (IgG) test results by demographic characteristics and clinical roles among a cohort of health care workers employed by the largest Midwestern health care system in the United States.MethodsWe collected 16 233 SARS-CoV-2 IgG serum samples from June 8 through July 10, 2020, from a convenience sample of Illinois- and Wisconsin-based adult health care workers. The research team, in collaboration with ACL Laboratories, used a SARS-CoV-2 IgG assay to detect the presence of SARS-CoV-2 IgG antibodies. Study data included SARS-CoV-2 IgG assay results and demographic characteristics of workers (age, sex, race, ethnicity, clinical role, zip code). We generated crude and adjusted odds ratios (ORs) to describe disparities in seroprevalence distribution among demographic and social factors.ResultsOf 16 233 IgG serum samples tested, 622 (3.8%) test results were positive for SARS-CoV-2. We found significant disparities in SARS-CoV-2 positivity by age, race, ethnicity, and clinical role. Participants aged 32-82 had lower adjusted ORs (aORs) of positive IgG than participants aged 18-31 (aOR range, 0.54-0.66). Odds of positivity were higher among Black (aOR = 3.86), Asian (aOR = 1.42), and mixed-race (aOR = 1.99) workers than among White workers; among Hispanic workers (aOR = 1.80) than among non-Hispanic workers; and among coronavirus disease 2019 (COVID-19) clinical workers (aOR = 1.86) than among nonclinical workers.ConclusionsPublic health efforts should focus on increasing COVID-19 safety messaging, testing, vaccination, and other prevention efforts for people who are young, non-White, Hispanic, and working in COVID-19–clinical units.     

The Effect of Test Timing on the Probability of Positive SARS-CoV-2 Swab Test Results: Mixed Model Approach

BackgroundDuring the COVID-19 pandemic, swab tests proved to be effective in containing the infection and served as a means for early diagnosis and contact tracing. However, little evidence exists regarding the correct timing for the execution of the swab test, especially for asymptomatic individuals and health care workers.ObjectiveThe objective of this study was to analyze changes in the positive findings over time in individual SARS-CoV-2 swab tests during a health surveillance program.MethodsThe study was conducted with 2071 health care workers at the University Hospital of Verona, with a known date of close contact with a patient with COVID-19, between February 29 and April 17, 2020. The health care workers underwent a health surveillance program with repeated swab tests to track their virological status. A generalized additive mixed model was used to investigate how the probability of a positive test result changes over time since the last known date of close contact, in an overall sample of individuals who tested positive for COVID-19 and in a subset of individuals with an initial negative swab test finding before being proven positive, to assess different surveillance time intervals.ResultsAmong the 2071 health care workers in this study, 191 (9.2%) tested positive for COVID-19, and 103 (54%) were asymptomatic with no differences based on sex or age. Among 49 (25.7%) cases, the initial swab test yielded negative findings after close contact with a patient with COVID-19. Sex, age, symptoms, and the time of sampling were not different between individuals with an initial negative swab test finding and those who initially tested positive after close contact. In the overall sample, the estimated probability of testing positive was 0.74 on day 1 after close contact, which increased to 0.77 between days 5 and 8. In the 3 different scenarios for scheduled repeated testing intervals (3, 5, and 7 days) in the subgroup of individuals with an initially negative swab test finding, the probability peaked on the sixth, ninth and tenth, and 13th and 14th days, respectively.ConclusionsSwab tests can initially yield false-negative outcomes. The probability of testing positive increases from day 1, peaking between days 5 and 8 after close contact with a patient with COVID-19. Early testing, especially in this final time window, is recommended together with a health surveillance program scheduled in close intervals.     

Risk Factors,Presentation, and Course of Coronavirus Disease 2019 in a Large,Academic Long-Term Care Facility

ObjectiveTo describe clinical characteristics and risk factors associated with coronavirus disease 2019 (COVID-19) in long-stay nursing home residents.Design and ParticipantsRetrospective cohort study (March 16, 2020 to May 8, 2020).SettingAcademic long-term chronic care facility (Boston, MA).ParticipantsLong-term care residents.MethodsPatient characteristics and clinical symptoms were obtained via electronic medical records and Minimum Data Set. Staff residence was inferred by zip codes. COVID-19 infection was confirmed by polymerase chain reaction testing using nasopharyngeal swabs. Residents were followed until discharge from facility, death, or up to 21 days. Risks of COVID-19 infection were modeled by generalized estimating equation to estimate the relative risk (RR) and 95% confidence intervals (CI) of patient characteristics and staff community of residence.ResultsOverall 146 of 389 (37.5%) long-stay residents tested positive for COVID-19. At the time of positive test, 66 of 146 (45.5%) residents were asymptomatic. In the subsequent illness course, the most common symptom was anorexia (70.8%), followed by delirium (57.6%). During follow-up, 44 (30.1%) of residents with COVID-19 died. Mortality increased with frailty (16.7% in pre-frail, 22.2% in moderately frail, and 50.0% in frail; P < .001). The proportion of residents infected with COVID-19 varied across the long-term care units (range: 0%‒90.5%). In adjusted models, male sex (RR 1.80, 95% CI 1.07, 3.05), bowel incontinence (RR 1.97, 95% CI 1.10, 3.52), and staff residence remained significant predictors of COVID-19. For every 10% increase in the proportion of staff living in a high prevalence community, the risk of testing positive increased by 6% (95% CI 1.04, 1.08).Conclusions and ImplicationsAmong long-term care residents diagnosed with COVID-19, nearly one-half were asymptomatic at the time of diagnosis. Predictors of COVID-19 infection included male sex, bowel incontinence, and staff residence in a community with a high burden of COVID-19. Universal testing of patients and staff in communities with high COVID-19 rates is essential to mitigate outbreaks.     

COVID-19 Surveillance in the Biobank at the Colorado Center for Personalized Medicine: Observational Study

BackgroundCharacterizing the experience and impact of the COVID-19 pandemic among various populations remains challenging due to the limitations inherent in common data sources, such as electronic health records (EHRs) or cross-sectional surveys.ObjectiveThis study aims to describe testing behaviors, symptoms, impact, vaccination status, and case ascertainment during the COVID-19 pandemic using integrated data sources.MethodsIn summer 2020 and 2021, we surveyed participants enrolled in the Biobank at the Colorado Center for Personalized Medicine (CCPM; N=180,599) about their experience with COVID-19. The prevalence of testing, symptoms, and impacts of COVID-19 on employment, family life, and physical and mental health were calculated overall and by demographic categories. Survey respondents who reported receiving a positive COVID-19 test result were considered a “confirmed case” of COVID-19. Using EHRs, we compared COVID-19 case ascertainment and characteristics in EHRs versus the survey. Positive cases were identified in EHRs using the International Statistical Classification of Diseases, 10th revision (ICD-10) diagnosis codes, health care encounter types, and encounter primary diagnoses.ResultsOf the 25,063 (13.9%) survey respondents, 10,661 (42.5%) had been tested for COVID-19, and of those, 1366 (12.8%) tested positive. Nearly half of those tested had symptoms or had been exposed to someone who was infected. Young adults (18-29 years) and Hispanics were more likely to have positive tests compared to older adults and persons of other racial/ethnic groups. Mental health (n=13,688, 54.6%) and family life (n=12,233, 48.8%) were most negatively affected by the pandemic and more so among younger groups and women; negative impacts on employment were more commonly reported among Black respondents. Of the 10,249 individuals who responded to vaccination questions from version 2 of the survey (summer 2021), 9770 (95.3%) had received the vaccine. After integration with EHR data up to the time of the survey completion, 1006 (4%) of the survey respondents had a discordant COVID-19 case status between EHRs and the survey. Using all longitudinal EHR and survey data, we identified 11,472 (6.4%) COVID-19-positive cases among Biobank participants. In comparison to COVID-19 cases identified through the survey, EHR-identified cases were younger and more likely to be Hispanic.ConclusionsWe found that the COVID-19 pandemic has had far-reaching and varying effects among our Biobank participants. Integrated data assets, such as the Biobank at the CCPM, are key resources for population health monitoring in response to public health emergencies, such as the COVID-19 pandemic.     

Infection fatality rate of COVID-19 inferred from seroprevalence data

ObjectiveTo estimate the infection fatality rate of coronavirus disease 2019 (COVID-19) from seroprevalence data.MethodsI searched PubMed and preprint servers for COVID-19 seroprevalence studies with a sample size ≥ 500 as of 9 September 2020. I also retrieved additional results of national studies from preliminary press releases and reports. I assessed the studies for design features and seroprevalence estimates. I estimated the infection fatality rate for each study by dividing the cumulative number of COVID-19 deaths by the number of people estimated to be infected in each region. I corrected for the number of immunoglobin (Ig) types tested (IgG, IgM, IgA).FindingsI included 61 studies (74 estimates) and eight preliminary national estimates. Seroprevalence estimates ranged from 0.02% to 53.40%. Infection fatality rates ranged from 0.00% to 1.63%, corrected values from 0.00% to 1.54%. Across 51 locations, the median COVID-19 infection fatality rate was 0.27% (corrected 0.23%): the rate was 0.09% in locations with COVID-19 population mortality rates less than the global average (< 118 deaths/million), 0.20% in locations with 118–500 COVID-19 deaths/million people and 0.57% in locations with > 500 COVID-19 deaths/million people. In people younger than 70 years, infection fatality rates ranged from 0.00% to 0.31% with crude and corrected medians of 0.05%.ConclusionThe infection fatality rate of COVID-19 can vary substantially across different locations and this may reflect differences in population age structure and case-mix of infected and deceased patients and other factors. The inferred infection fatality rates tended to be much lower than estimates made earlier in the pandemic.     

Does BCG provide long-term protection against SARS-CoV-2 infection? A case–control study in Quebec,Canada

BackgroundEarly in the coronavirus disease 2019 (COVID-19) pandemic, before severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines became available, it was hypothesized that BCG (Bacillus Calmette–Guérin), which stimulates innate immunity, could provide protection against SARS-CoV-2. Numerous ecological studies, plagued by methodological deficiencies, revealed a country-level association between BCG use and lower COVID-19 incidence and mortality. We aimed to determine whether BCG administered in early life decreased the risk of SARS-CoV-2 infection in adulthood and the severity of COVID-19.MethodsThis case-control study was conducted in Quebec, Canada. Cases were patients with a positive SARS-CoV-2 nucleic acid amplification test performed at two hospitals between March–October 2020. Controls were identified among patients with non-COVID-19 samples processed by the same microbiology laboratories during the same period. Enrolment was limited to individuals born in Quebec between 1956 and 1976, whose vaccine status was accessible in a computerized registry of 4.2 million BCG vaccinations.ResultsWe recruited 920 cases and 2123 controls. Fifty-four percent of cases (n = 424) and 53% of controls (n = 1127) had received BCG during childhood (OR: 1.03; 95% CI: 0.89–1.21), while 12% of cases (n = 114) and 11% of controls (n = 235) had received two or more BCG doses (OR: 1.14; 95% CI: 0.88–1.46). After adjusting for age, sex, material deprivation, recruiting hospital and occupation there was no evidence of protection conferred by BCG against SARS-CoV-2 (AOR: 1.01; 95% CI: 0.84–1.21). Among cases, 77 (8.4%) needed hospitalization and 18 (2.0%) died. The vaccinated were as likely as the unvaccinated to require hospitalization (AOR: 1.01, 95% CI: 0.62–1.67) or to die (AOR: 0.85, 95% CI: 0.32–2.39).ConclusionsBCG does not provide long-term protection against symptomatic COVID-19 or severe forms of the disease.     

河南省入境超14天首次核酸阳性和出院后复检核酸阳性新冠肺炎感染者分析

目的 分析河南省入境超14 d首次核酸检测阳性和出院后核酸复测阳性（复阳）的境外输入新冠肺炎感染者特征。方法 将河南省2020年3月10日至2022年3月14日境外输入752例新冠肺炎感染者作为研究对象,收集其流行病学、实验室检测等信息,用χ2检验和秩和检验进行统计分析,描述入境超14 d检测阳性和复阳病例的特点。结果 收集到684例感染者入境及核酸检测时间,入境超14 d首次核酸检测阳性感染者共20例(2.92%),其中无症状感染者19例,确诊病例1例;男性19例,女性1例;跨省活动18例;完成全程接种7例;年龄中位数为40.5（30.25,48.5）岁;住院时长中位数为17（15.25,25） d。入境超14 d检测阳性病例中男性构成高于14 d内阳性病例中男性构成（χ2 = 4.463,P = 0.035）,年龄大于后者（Z = - 2.265,P = 0.024）,疫苗全程接种率低于后者（P＜0.001）,无症状感染者占比高于后者（χ2 = 4.687,P = 0.030）。752例感染者中复阳15例,复阳率为1.99%。另收集到10例在第一入境点治愈后返回河南复阳感染者,共25例。首次核酸阳性治愈出院到复阳时间间隔在1～297 d之间,中位数为13（3.25,26.75）d;复阳时ORF1ab基因CT值中位数为35.05（32.00,36.44）,N基因中位数为35.62（32.91,36.55）;发现复阳时集中隔离17例,居家隔离4例,自由活动4例;首次核酸阳性诊断为无症状感染者12例,确诊病例13例;复阳诊断为无症状感染者22例,确诊病例3例;复阳病例中首次诊断为确诊病例的比例高于非复阳病例（χ2 = 6.223,P = 0.013）;复阳病例未造成二代传播。结论 入境超14 d检出阳性者更多为无症状感染者,复阳病例核酸CT值较高,首诊确诊病例更易出现复阳,未发现入境复阳病例造成二代传播。     

Predictors of COVID-19 vaccine uptake among people who inject drugs

IntroductionWe studied characteristics of COVID-19 vaccination uptake among people who inject drugs (PWID).MethodsParticipants aged ≥18 years who injected drugs ≤1 month ago were recruited into a community-based cohort from October 2020 to September 2021 in San Diego, California Poisson regression identified correlates of having had ≥1 COVID-19 vaccine dose based on semi-annual follow-up interviews through March 15, 2022.ResultsOf 360 participants, 74.7% were male, mean age was 42 years; 63.1% were Hispanic/Mexican/Latinx. More than one-third had ≥1 co-morbidity. HIV and HCV seroprevalence were 4.2% and 50.6% respectively; 41.1% lacked health insurance. Only 37.8% reported having ≥1 COVID-19 vaccine dose. None received ≥3 doses. However, of those vaccinated, 37.5% were previously unwilling/unsure about COVID-19 vaccines. Believing COVID-19 vaccines include tracking devices (adjusted incidence rate ratio [aIRR]: 0.62; 95% CI: 0.42,0.92) and lacking health insurance (aIRR: 0.60; 95% CI: 0.40,0.91) were associated with approximately 40% lower COVID-19 vaccination rates). Ever receiving influenza vaccines (aIRR: 2.16; 95%CI: 1.46, 3.20) and testing HIV-seropositive (aIRR: 2.51; 95% CI: 1.03, 6.10) or SARS-CoV-2 RNA-positive (aIRR: 1.82; 95% CI: 1.05, 3.16) independently predicted higher COVID-19 vaccination rates. Older age, knowing more vaccinated people, and recent incarceration were also independently associated with higher COVID-19 vaccination rates.ConclusionsOne year after COVID-19 vaccines became available to U.S. adults, only one third of PWID had received ≥1 COVID-19 vaccine dose. Multi-faceted approaches that dispel disinformation, integrate public health and social services and increase access to free, community-based COVID-19 vaccines are urgently needed.     

Community Coronavirus Disease 2019 Activity Level and Nursing Home Staff Testing for Active Severe Acute Respiratory Syndrome Coronavirus 2 Infection in Indiana

ObjectivesTo assess whether using coronavirus disease 2019 (COVID-19) community activity level can accurately inform strategies for routine testing of facility staff for active severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.DesignCross-sectional study.Setting and ParticipantsIn total, 59,930 nursing home staff tested for active SARS-CoV-2 infection in Indiana.MeasuresReceiver operator characteristic curves and the area under the curve to compare the sensitivity and specificity of identifying positive cases of staff within facilities based on community COVID-19 activity level including county positivity rate and county cases per 10,000.ResultsThe detection of any infected staff within a facility using county cases per 10,000 population or county positivity rate resulted in an area under the curve of 0.648 (95% confidence interval 0.601?0.696) and 0.649 (95% confidence interval 0.601?0.696), respectively. Of staff tested, 28.0% were certified nursing assistants, yet accounted for 36.9% of all staff testing positive. Similarly, licensed practical nurses were 1.4% of staff, but 4.7% of positive cases.Conclusions and ImplicationsWe failed to observe a meaningful threshold of community COVID-19 activity for the purpose of predicting nursing homes with any positive staff. Guidance issued by the Centers for Medicare and Medicaid Services in August 2020 sets the minimum frequency of routine testing for nursing home staff based on county positivity rates. Using the recommended 5% county positivity rate to require weekly testing may miss asymptomatic infections among nursing home staff. Further data on results of all-staff testing efforts, particularly with the implementation of new widespread strategies such as point-of-care testing, is needed to guide policy to protect high-risk nursing home residents and staff. If the goal is to identify all asymptomatic SARS-Cov-2 infected nursing home staff, comprehensive repeat testing may be needed regardless of community level activity.     

COVID-19 vaccine uptake and intention during pregnancy in Canada

ObjectiveTo investigate COVID-19 vaccine uptake and intent among pregnant people in Canada, and determine associated factors.MethodsWe conducted a national cross-sectional survey among pregnant people from May 28 through June 7, 2021 (n = 193). Respondents completed a questionnaire to determine COVID-19 vaccine acceptance (defined as either received or intend to receive a COVID-19 vaccine during pregnancy), factors associated with vaccine acceptance, and rationale for accepting/not accepting the vaccine.ResultsOf 193 respondents, 57.5% (n = 111) reported COVID-19 vaccine acceptance. Among those who did not accept the vaccine, concern over vaccine safety was the most commonly cited reason (90.1%, n = 73), and 81.7% (n = 67) disagreed with receiving a vaccine that had not been tested in pregnant people. Confidence in COVID-19 vaccine safety (aOR 16.72, 95% CI: 7.22, 42.39), Indigenous self-identification (aOR 11.59, 95% CI: 1.77, 117.18), and employment in an occupation at high risk for COVID-19 exposure excluding healthcare (aOR 4.76, 95% CI: 1.32, 18.60) were associated with vaccine acceptance. Perceived personal risk of COVID-19 disease was not associated with vaccine acceptance in the multivariate model.ConclusionVaccine safety is a primary concern for this population. Safety information should be communicated to this population as it emerges, along with clear messaging on the benefits of vaccination, as disease risk is either poorly understood or poorly valued in this population.     

Receipt of COVID-19 and seasonal influenza vaccines in California (USA) during the 2021–2022 influenza season

BackgroundDespite lower circulation of influenza virus throughout 2020–2022 during the COVID-19 pandemic, seasonal influenza vaccination has remained a primary tool to reduce influenza-associated illness and death. The relationship between the decision to receive a COVID-19 vaccine and/or an influenza vaccine is not well understood.MethodsWe assessed predictors of receipt of 2021–2022 influenza vaccine in a secondary analysis of data from a case-control study enrolling individuals who received SARS-CoV-2 testing. We used mixed effects logistic regression to estimate factors associated with receipt of seasonal influenza vaccine. We also constructed multinomial adjusted marginal probability models of being vaccinated for COVID-19 only, seasonal influenza only, or both as compared with receipt of neither vaccination.ResultsAmong 1261 eligible participants recruited between 22 October 2021–22 June 2022, 43% (545) were vaccinated with both seasonal influenza vaccine and >1 dose of a COVID-19 vaccine, 34% (426) received >1 dose of a COVID-19 vaccine only, 4% (49) received seasonal influenza vaccine only, and 19% (241) received neither vaccine. Receipt of >1 COVID-19 vaccine dose was associated with seasonal influenza vaccination (adjusted odds ratio [aOR]: 3.72; 95% confidence interval [CI]: 2.15–6.43); this association was stronger among participants receiving >1 COVID-19 booster dose (aOR = 16.50 [10.10–26.97]). Compared with participants testing negative for SARS- CoV-2 infection, participants testing positive had lower odds of receipt of 2021-2022 seasonal influenza vaccine (aOR = 0.64 [0.50–0.82]).ConclusionsRecipients of a COVID-19 vaccine were more likely to receive seasonal influenza vaccine during the 2021–2022 season. Factors associated with individuals’ likelihood of receiving COVID-19 and seasonal influenza vaccines will be important to account for in future studies of vaccine effectiveness against both conditions. Participants who tested positive for SARS-CoV-2 in our sample were less likely to have received seasonal influenza vaccine, suggesting an opportunity to offer influenza vaccination before or after a COVID-19 diagnosis.     

某国际测试赛新型冠状病毒核酸阳性应急处置情况分析与经验交流

目的 对某冬奥会竞赛场馆举办的国际测试活动中新型冠状病毒肺炎应急事件处置情况进行回顾性分析,为同类赛事疫情防控工作提供科学参考。方法 通过回顾性分析法,对新型冠状病毒核酸阳性人员的流行病学调查、核酸检测、沟通对接等防控措施落实情况进行描述分析。结果 在入境前、机场、住地及场馆均报告了入境人员核酸阳性,其中入境前阳性2例,入境后既往感染者复阳2例,无症状感染者3例。场馆与属地协同高效开展流行病学调查,未发生本土疫情传播,但阳性人员核酸检测结果波动,为防控措施落实带来巨大挑战。结论 在大型国际赛事中,境外输入疫情形势严峻,核酸检测结果的波动、阳性的判定与解除标准,以及在事件处置中人性化关怀需充分考虑。     

Vaccine effectiveness against COVID-19 related hospital admission in the Netherlands: A test-negative case-control study

IntroductionReal-world vaccine effectiveness (VE) estimates are essential to identify potential groups at higher risk of break-through infections and to guide policy. We assessed the VE of COVID-19 vaccination against COVID-19 hospitalization, while adjusting and stratifying for patient characteristics.MethodsWe performed a test-negative case-control study in six Dutch hospitals. The study population consisted of adults eligible for COVID-19 vaccination hospitalized between May 1 and June 28, 2021 with respiratory symptoms. Cases were defined as patients who tested positive for SARS-CoV-2 by PCR during the first 48 h of admission or within 14 days prior to hospital admission. Controls were patients tested negative at admission and did not have a positive test during the 2 weeks prior to hospitalization. VE was calculated using multivariable logistic regression, adjusting for calendar week, sex, age, comorbidity and nursing home residency. Subgroup analysis was performed for age, sex and different comorbidities. Secondary endpoints were ICU-admission and mortality.Results379 cases and 255 controls were included of whom 157 (18%) were vaccinated prior to admission. Five cases (1%) and 40 controls (16%) were fully vaccinated (VE: 93%; 95% CI: 81 – 98), and 40 cases (11%) and 70 controls (27%) were partially vaccinated (VE: 70%; 95% CI: 50–82). A strongly protective effect of vaccination was found in all comorbidity subgroups. No ICU-admission or mortality were reported among fully vaccinated cases. Of unvaccinated cases, mortality was 10% and 19% was admitted at the ICU.ConclusionCOVID-19 vaccination provides a strong protective effect against COVID-19 related hospital admission, in patients with and without comorbidity.     

Serologic Survey of IgG Against SARS-CoV-2 Among Hospital Visitors Without a History of SARS-CoV-2 Infection in Tokyo, 2020–2021

BackgroundTokyo, the capital of Japan, is a densely populated city of >13 million people, so the population is at high risk of epidemic severe acute respiratory coronavirus 2 (SARS-CoV-2) infection. A serologic survey of anti–SARS-CoV-2 IgG would provide valuable data for assessing the city’s SARS-CoV-2 infection status. Therefore, this cross-sectional study estimated the anti–SARS-CoV-2 IgG seroprevalence in Tokyo.MethodsLeftover serum of 23,234 hospital visitors was tested for antibodies against SARS-CoV-2 using an iFlash 3000 chemiluminescence immunoassay analyzer (Shenzhen YHLO Biotech, Shenzhen, China) with an iFlash–SARS-CoV-2 IgG kit (YHLO) and iFlash–SARS-CoV-2 IgG-S1 kit (YHLO). Serum samples with a positive result (≥10 AU/mL) in either of these assays were considered seropositive for anti–SARS-CoV-2 IgG. Participants were randomly selected from patients visiting 14 Tokyo hospitals between September 1, 2020 and March 31, 2021. No participants were diagnosed with coronavirus disease 2019 (COVID-19), and none exhibited COVID-19-related symptoms at the time of blood collection.ResultsThe overall anti–SARS-CoV-2 IgG seroprevalence among all participants was 1.83% (95% confidence interval [CI], 1.66–2.01%). The seroprevalence in March 2021, the most recent month of this study, was 2.70% (95% CI, 2.16–3.34%). After adjusting for population age, sex, and region, the estimated seroprevalence in Tokyo was 3.40%, indicating that 470,778 individuals had a history of SARS-CoV-2 infection.ConclusionsThe estimated number of individuals in Tokyo with a history of SARS-CoV-2 infection was 3.9-fold higher than the number of confirmed cases. Our study enhances understanding of the SARS-CoV-2 epidemic in Tokyo.Key words: SARS-CoV-2, COVID-19, IgG seroprevalence, hospital visitors, Tokyo     

Adverse Events Following One Dose of mRNA COVID-19 Vaccination Among US Nursing Home Residents With and Without a Previous SARS-CoV-2 Infection

ObjectivesTo compare rates of adverse events following Coronavirus Disease 2019 (COVID-19) vaccination among nursing home residents with and without previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.DesignProspective cohort.Setting and ParticipantsA total of 20,918 nursing home residents who received the first dose of messenger RNA COVID-19 vaccine from December 18, 2020, through February 14, 2021, in 284 facilities within Genesis Healthcare, a large nursing home provider spanning 24 US states.MethodsWe screened the electronic health record for adverse events, classified by the Brighton Collaboration, occurring within 15 days of a resident’s first COVID-19 vaccine dose. All events were confirmed by physician chart review. To obtain risk ratios, multilevel logistic regression model that accounted for clustering (variability) across nursing homes was implemented. To balance the probability of prior SARS-CoV-2 infection (previous positive test or diagnosis by the International Classification of Diseases, 10^th Revision, Clinical Modification) more than 20 days before vaccination, we used inverse probability weighting. To adjust for multiplicity of adverse events tested, we used a false discovery rate procedure.ResultsStatistically significant differences existed between those without (n = 13,163) and with previous SARS-CoV-2 infection [symptomatic (n = 5617) and asymptomatic (n = 2138)] for all baseline characteristics assessed. Only 1 adverse event was reported among those with previous SARS-CoV-2 infection (asymptomatic), venous thromboembolism [46.8 per 100,000 residents 95% confidence interval (CI) 8.3–264.5], which was not significantly different from the rate reported for those without previous infection (30.4 per 100,000 95% CI 11.8–78.1). Several other adverse events were observed for those with no previous infection, but were not statistically significantly higher than those reported with previous infection after adjustments for multiple comparisons.Conclusions and ImplicationsAlthough reactogenicity increases with preexisting immunity, we did not find that vaccination among those with previous SARS-CoV-2 infection resulted in higher rates of adverse events than those without previous infection. This study stresses the importance of monitoring novel vaccines for adverse events in this vulnerable population.     

Covid-19 infection and diffusion among the healthcare workforce in a large university-hospital in northwest Italy

Backgroud:Since the beginning of the coronavirus disease 2019 (COVID-19) outbreak, healthcare workers (HCWs) have been the workers most likely to contract the disease. Intensive focus is therefore needed on hospital strategies that minimize exposure and diffusion, confer protection and facilitate early detection and isolation of infected personnel.Methods:To evaluate the early impact of a structured risk-management for exposed COVID-19 HCWs and describe how their characteristics contributed to infection and diffusion. Socio-demographic and clinical data, aspects of the event-exposure (date, place, length and distance of exposure, use of PPE) and details of the contact person were collected.Results:The 2411 HCWs reported 2924 COVID-19 contacts. Among 830 HCWs who were at ‘high or medium risk’, 80 tested positive (9.6%). Physicians (OR=2.03), and non-medical services resulted in an increased risk (OR=4.23). Patient care did not increase the risk but sharing the work environment did (OR=2.63). There was a significant time reduction between exposure and warning, exposure and test, and warning and test since protocol implementation. HCWs with management postitions were the main source of infection due to the high number of interactions.Discussion:A proactive system that includes prompt detection of contagious staff and identification of sources of exposure helps to lower the intra-hospital spread of infection. A speedier return to work of staff who would otherwise have had to self-isolate as a precautionary measure improves staff morale and patient care by reducing the stress imposed by excessive workloads arising from staff shortages.Key words: Infection diffusion, social network analysis, healthcare professionals, occupational health, COVID-19