Hybrid Immunity Provides Protective Advantage Over Vaccination or Prior Remote Coronavirus Disease 2019 Alone.

Background: The protective efficacy of prior coronavirus disease 2019 (COVID-19) with or without vaccination remains unknown. This study sought to understand if 2 or more messenger RNA (mRNA) vaccine doses provide additional protection in patients with prior infection, or if infection alone provides comparable protection. Methods: We conducted a retrospective cohort study of the risk of COVID-19 from 16 December 2020 through 15 March 2022, among vaccinated and unvaccinated patients of all ages with and without prior infection. A Simon-Makuch hazard plot illustrated the incidence of COVID-19 between groups. Multivariable Cox proportional hazards regression was used to examine the association of demographics, prior infection, and vaccination status with new infection. Results: Among 101 941 individuals with at least 1 COVID-19 polymerase chain reaction test prior to 15 March 2022, 72 361 (71.0%) received mRNA vaccination and 5957 (5.8%) were previously infected. The cumulative incidence of COVID-19 was substantially higher throughout the study period for those previously uninfected and unvaccinated, and lowest for those previously infected and vaccinated. After accounting for age, sex, and the interaction between vaccination and prior infection, a reduction in reinfection risk was noted during the Omicron and pre-Omicron phases of 26% (95% confidence interval [CI], 8%-41%; P = .0065) to 36% (95% CI, 10%-54%; P = .0108), respectively, among previously infected and vaccinated individuals, compared to previously infected subjects without vaccination. Conclusions: Vaccination was associated with lower risk of COVID-19, including in those with prior infection. Vaccination should be encouraged for all including those with prior infection, especially as new variants emerge and variant-specific booster vaccines become available.

Who is getting boosted? Disparities in COVID-19 vaccine booster uptake among health care workers.

COVID-19 vaccination remains one of the most effective tools to reduce the risk of SARS-CoV-2 infection. Unfortunately, vaccine hesitancy has limited primary vaccination and booster uptake among the general population and HCWs. To gain a better understanding of factors associated with booster vaccine uptake, we analyzed COVID-19 vaccine booster rates among HCWs and identified risk factors associated with nonacceptance. Of the 62,387 HCWs included in our analysis, the overall booster uptake rate was 64.8%. Older age, Non-Hispanic White racial group, early initial vaccine uptake and longer duration of employment were associated with higher booster uptake. Significant differences were observed between different job categories. This persistence of vaccine hesitancy and disparities in COVID-19 booster uptake among HCWs, almost 2 years after the rollout of the COVID-19 vaccination, call for further efforts to increase vaccine confidence among HCWs and the general population in light of the continued need for further COVID-19 protection.

A Multisite Assessment of Inpatient Safety Event Rates During the Coronavirus Disease 2019 Pandemic.

To date, there has been a notable lack of peer-reviewed or publicly available data documenting rates of hospital quality outcomes and patient safety events during the coronavirus disease 2019 pandemic era. The dearth of evidence is perhaps related to the US health care system triaging resources toward patient care and away from reporting and research and also reflects that data used in publicly reported hospital quality rankings and ratings typically lag 2-5 years. At our institution, a learning health system assessment is underway to evaluate how patient safety was affected by the pandemic. Here we share and discuss early findings, noting the limitations of self-reported safety event reporting, and suggest the need for further widespread investigations at other US hospitals. During the 2-year study period from January 1, 2020, through December 31, 2021 across 3 large US academic medical centers at our institution, we documented an overall rate of 25.8 safety events per 1000 inpatient days. The rate of events meeting "harm" criteria was 12.4 per 1000 inpatient days, the rate of nonharm events was 11.1 per 1000 inpatient days, and the fall rate was 2.3 per 1000 inpatient days. This descriptive exploratory analysis suggests that patient safety event rates at our institution did not increase over the course of the pandemic. However, increasing health care worker absences were nonlinearly and strongly associated with patient safety event rates, which raises questions regarding the mechanisms by which patient safety event rates may be affected by staff absences during pandemic peaks.

Occupational exposure to severe acute respiratory coronavirus virus 2 (SARS-CoV-2) and risk of infection among healthcare personnel.

OBJECTIVE: To assess the rate and factors associated with healthcare personnel (HCP) testing positive for severe acute respiratory coronavirus virus 2 (SARS-CoV-2) after an occupational exposure. DESIGN: Retrospective cohort study. SETTING: Academic medical center with sites in Minnesota, Wisconsin, Arizona, and Florida. PARTICIPANTS: HCP with a high or medium risk occupational exposure to a patient or other HCP with SARS-CoV-2. METHODS: We reviewed the records of HCP with significant occupational exposures from March 20, 2020, through December 31, 2020. We then performed regression analysis to assess the impact of demographic and occupational variables to assess their impact on the likelihood of testing positive for SARS-CoV-2. RESULTS: In total, 2,253 confirmed occupational exposures occurred during the study period. Employees were the source for 57.1% of exposures. Overall, 101 HCP (4.5%) tested positive in the postexposure period. Of these, 80 had employee sources of exposure and 21 had patient sources of exposure. The postexposure infection rate was 6.2% when employees were the source, compared to 2.2% with patient sources. In a multivariate analysis, occupational exposure from an employee source had a higher risk of testing positive compared to a patient source (odds ratio [OR], 3.22; 95% confidence interval [CI], 1.72-6.04). Sex, age, high-risk exposure, and HCP role were not associated with an increased risk of testing positive. CONCLUSIONS: The risk of acquiring coronavirus disease 2019 (COVID-19) following a significant occupational exposure has remained relatively low, even in the prevaccination era. Exposure to an infectious coworker carries a higher risk than exposure to a patient. Continued vigilance and precautions remain necessary in healthcare settings.

Healthcare personnel absenteeism, presenteeism, and staffing challenges during epidemics.

OBJECTIVE: Presenteeism is an expensive and challenging problem in the healthcare industry. In anticipation of the staffing challenges expected with the COVID-19 pandemic, we examined a decade of payroll data for a healthcare workforce. We aimed to determine the effect of seasonal influenza-like illness (ILI) on absences to support COVID-19 staffing plans. DESIGN: Retrospective cohort study. SETTING: Large academic medical center in the United States. PARTICIPANTS: Employees of the academic medical center who were on payroll between the years of 2009 and 2019. METHODS: Biweekly institutional payroll data was evaluated for unscheduled absences as a marker for acute illness-related work absences. Linear regression models, stratified by payroll status (salaried vs hourly employees) were developed for unscheduled absences as a function of local ILI. RESULTS: Both hours worked and unscheduled absences were significantly related to the community prevalence of influenza-like illness in our cohort. These effects were stronger in hourly employees. CONCLUSIONS: Organizations should target their messaging at encouraging salaried staff to stay home when ill.

Utility of Follow-up Coronavirus Disease 2019 (COVID-19) Antigen Tests After Acute Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection Among Healthcare Personnel.

We report the utility of rapid antigen tests (RAgT) in a cohort of US healthcare personnel with coronavirus disease 2019 (COVID-19) infection who met symptom criteria to return to work at day 5 or later of isolation. In total, 11.9% of initial RAgT were negative. RAgT can be helpful to guide return to work decisions.

Evaluation of healthcare personnel exposures to patients with severe acute respiratory coronavirus virus 2 (SARS-CoV-2) associated with personal protective equipment.

OBJECTIVE: Personal protective equipment (PPE) is a critical aspect of preventing the transmission of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) in healthcare settings. We aimed to identify factors related to lapses in PPE use that may influence transmission of SARS-CoV-2 from patients to healthcare personnel (HCP). DESIGN: Retrospective cohort study. SETTING: Tertiary-care medical center in Minnesota. PARTICIPANTS: In total, 345 HCP who sustained a significant occupational exposure to a patient with coronavirus disease 2019 (COVID-19) from May 13, 2020, through November 30, 2020, were evaluated. RESULTS: Overall, 8 HCP (2.3%) were found to have SARS-CoV-2 infection during their 14-day postexposure quarantine. A lack of eye protection during the care of a patient with COVID-19 was associated with HCP testing positive for SARS-CoV-2 by reverse-transcriptase polymerase chain reaction (RT-PCR) during the postexposure quarantine (relative risk [RR], 10.25; 95% confidence interval [CI], 1.28-82.39; P = .009). Overall, the most common reason for a significant exposure was the use of a surgical face mask instead of a respirator during an aerosol-generating procedure (55.9%). However, this was not associated with HCP testing positive for SARS-CoV-2 during the postexposure quarantine (RR, 0.99; 95% CI, 0.96-1; P = 1). Notably, transmission primarily occurred in units that did not regularly care for patients with COVID-19. CONCLUSIONS: The use of universal eye protection is a critical aspect of PPE to prevent patient-to-HCP transmission of SARS-CoV-2.

Work Absence Following COVID-19 Vaccination in a Cohort of Healthcare Personnel.

OBJECTIVE: To identify rates of work absence following receipt of COVID-19 vaccine in a cohort of healthcare personnel (HCP). METHODS: Short-term disability (STD) usage by HCP attributed to side effects of the COVID-19 vaccine was calculated for each vaccine manufacturer, job category, age group, and work region. Analysis was performed for the cohort of HCP during the initial vaccination campaign. RESULTS: 4.1% of COVID-19 vaccinations generated a STD claim for lost work due to side effects, with increased STD rates after dose 2 than dose 1 (7.4% and 0.9%, respectively). Rates were higher for younger HCP and allied health staff. CONCLUSIONS: While side effects from mRNA vaccine dose 2 resulted in more work absence, statistically significant geographic differences in STD suggest cultural and staffing factors may impact HCP to utilize STD following vaccination.

Effectiveness of Messenger RNA Coronavirus Disease 2019 (COVID-19) Vaccines Against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection in a Cohort of Healthcare Personnel.

In a large cohort of United States healthcare personnel without prior coronavirus disease 2019 (COVID-19) infection, 94 382 doses of messenger RNA (mRNA) COVID-19 vaccine were administered to 49 220 individuals. The adjusted vaccine effectiveness following 2 doses of each of the 2 available brands of mRNA vaccine exceeded 96%.

Combined Effects of Masking and Distance on Aerosol Exposure Potential.

OBJECTIVE: To quantify the efficacy of masking and "social distancing" on the transmission of airborne particles from a phantom aerosol source (simulating an infected individual) to a nearby target (simulating a healthy bystander) in a well-controlled setting. METHODS: An aerosol was created using monodisperse polystyrene latex beads in place of infectious respiratory secretions. Detection was by aerodynamic particle spectrometry. Both reusable cloth masks and disposable paper masks were studied. Transmission was simulated indoors during a 3-minute interval to eliminate the effect of variable ventilation rate on aerosol exposure. The study commenced on September 16, 2020, and concluded on December 15, 2020. RESULTS: Compared with a baseline of 1-foot separation with no masks employed, particle count was reduced by 84% at 3 feet of separation and 97% at 6 feet. A modest decrease in particle count was observed when only the receiver was masked. The most substantial exposure reduction occurred when the aerosol source was masked (or both parties were masked). When both the source and target were masked, particle count was reduced by more than 99.5% of baseline, regardless of separation distance or which type of mask was employed. CONCLUSION: These results support the principle of layered protection to mitigate transmission of SARS-CoV-2, the virus causing COVID-19, and other respiratory viruses and emphasize the importance of controlling the spread of aerosol at its source. The combination of masking and distancing reduced the exposure to exhaled particulates more than any individual measure. Combined measures remain the most effective way to combat the spread of respiratory infection.

Prevalence of SARS-CoV-2 Antibodies in a Multistate Academic Medical Center.

OBJECTIVE: To estimate the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in health care personnel. METHODS: The Mayo Clinic Serology Screening Program was created to provide a voluntary, two-stage testing program for SARS-CoV-2 antibodies to health care personnel. The first stage used a dried blood spot screening test initiated on June 15, 2020. Those participants identified as reactive were advised to have confirmatory testing via a venipuncture. Venipuncture results through August 8, 2020, were considered. Consent and authorization for testing was required to participate in the screening program. This report, which was conducted under an institutional review board-approved protocol, only includes employees who have further authorized their records for use in research. RESULTS: A total of 81,113 health care personnel were eligible for the program, and of these 29,606 participated in the screening program. A total of 4284 (14.5%) of the dried blood spot test results were "reactive" and warranted confirmatory testing. Confirmatory testing was completed on 4094 (95.6%) of the screen reactive with an overall seroprevalence rate of 0.60% (95% CI, 0.52% to 0.69%). Significant variation in seroprevalence was observed by region of the country and age group. CONCLUSION: The seroprevalence for SARS-CoV-2 antibodies through August 8, 2020, was found to be lower than previously reported in other health care organizations. There was an observation that seroprevalence may be associated with community disease burden.