COVID-19 vaccine impact on rates of SARS-CoV-2 cases and post vaccination strain sequences among healthcare workers at an urban academic medical center: a prospective cohort study.

BACKGROUND: COVID-19 vaccine trials and post-implementation data suggest vaccination decreases SARS-CoV-2 infections. We examine COVID-19 vaccination's impact on SARS-CoV-2 case rates and viral diversity among healthcare workers (HCW) during a high community prevalence period. METHODS: A prospective cohort study from Boston Medical Center (BMC)'s HCW vaccination program, where staff received two doses of BNT162b2 or mRNA-1273. We included PCR-confirmed SARS-CoV-2 cases among HCWs from December 09, 2020 to February 23, 2021. Weekly SARS-CoV-2 rates per 100,000 person-day overall and by time from first injection (1-14 and >14 days) were compared with surrounding community rates. Viral genomes were sequenced from SARS CoV-2 positive samples. RESULTS: SARS-CoV-2 cases occurred in 1.4% (96/7109) of HCWs given at least a first dose and 0.3% (17/5913) of HCWs given both vaccine doses. Adjusted SARS-CoV-2 infection rate ratios were 0.73 (95% CI 0.53-1.00) 1-14 days and 0.18 (0.10-0.32) >14 days from first dose. HCW SARS-CoV-2 cases >14 days from initial dose compared to within 14 days were more often older (46 versus 38 years, p=0.007), Latinx (10% versus 8%, p=0.03), and asymptomatic (48% versus 11%, p=0.0002). SARS-CoV-2 rates among HCWs fell below those of the surrounding community, with a 18% versus 11% weekly decrease respectively (p=0.14). Comparison of 48 SARS-CoV-2 genomes sequenced from post-first dose cases did not indicate selection pressure towards known spike-antibody escape mutations. CONCLUSIONS: Our results indicate a positive impact of COVID-19 vaccines on SARS-CoV-2 case rates. Post-vaccination isolates did not show unusual genetic diversity or selection for mutations of concern. MAIN POINT: Cases of SARS-CoV-2 among health care workers dropped rapidly with COVID-19 vaccination. Sequencing 48 breakthrough infections (overwhelmingly in 14 days after 1st dose) showed no clear sign of any differences in spike protein compared with time-matched, unvaccinated control sequences.

Coronavirus Disease 2019 Vaccine Impact on Rates of Severe Acute Respiratory Syndrome Coronavirus 2 Cases and Postvaccination Strain Sequences Among Health Care Workers at an Urban Academic Medical Center: A Prospective Cohort Study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) vaccine trials and post-implementation data suggest that vaccination decreases infections. We examine vaccination's impact on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) case rates and viral diversity among health care workers (HCWs) during a high community prevalence period. METHODS: In this prospective cohort study, HCW received 2 doses of BNT162b2 or mRNA-1273. We included confirmed cases among HCWs from 9 December 2020 to 23 February 2021. Weekly SARS-CoV-2 rates per 100,000 person-days and by time from first injection (1-14 and ≥15 days) were compared with surrounding community rates. Viral genomes were sequenced. RESULTS: SARS-CoV-2 cases occurred in 1.4% (96/7109) of HCWs given at least a first dose and 0.3% (17/5913) of HCWs given both vaccine doses. Adjusted rate ratios (95% confidence intervals) were 0.73 (.53-1.00) 1-14 days and 0.18 (.10-.32) ≥15 days from first dose. HCW ≥15 days from initial dose compared to 1-14 days were more often older (46 vs 38 years, P = .007), Latinx (10% vs 8%, P = .03), and asymptomatic (48% vs 11%, P = .0002). SARS-CoV-2 rates among HCWs fell below the surrounding community, an 18% vs 11% weekly decrease, respectively (P = .14). Comparison of 50 genomes from post-first dose cases did not indicate selection pressure toward known spike antibody escape mutations. CONCLUSIONS: Our results indicate an early positive impact of vaccines on SARS-CoV-2 case rates. Post-vaccination isolates did not show unusual genetic diversity or selection for mutations of concern.

The role of tissue plasminogen activator use and systemic hypercoagulability in central line-associated bloodstream infections.

BACKGROUND: Central line-associated bloodstream infections (CLABSIs) impact patient outcomes and increase cost of hospitalization. In situ thrombus is known to promote microbial adhesion and colonization and potentially lead to CLABSI. Clinical validation of this theory, adjusting for presence of systemic hypercoagulability, is needed. METHODS: This study is a retrospective review of all adult and pediatric patients with peripherally inserted central catheter placement over a 4-year period at our tertiary care center. Tissue plasminogen activator (TPA) use was utilized as indicator for line site thrombus. CLABSIs rates were compared in patients with or without TPA use, adjusting for the presence of hypercoagulable conditions, age, and severity of illness. RESULTS: A total of 3,723 patients with peripherally inserted central catheter lines was evaluated, 40% of whom received TPA. The adjusted odds of developing a CLABSI was 3.59 times greater in those patients who received TPA compared with those who did not (95% confidence interval [CI]: 1.86-6.94). Neither severity of illness (odds ratio [OR], 1.00; 95% CI: 0.51-1.96) nor primary (OR, 3.41; 95% CI: 0.43-26.7) or secondary hypercoagulability (OR, 0.91; 95% CI: 0.44-1.88) were statistically associated with a higher risk of infection. CONCLUSION: The use of TPA, as a possible indicator in situ thrombus, was associated with a higher risk of developing CLABSI. Neither primary nor secondary hypercoagulability was correlated with risk of developing CLABSI.

Adherence to ventilator-associated pneumonia bundle and incidence of ventilator-associated pneumonia in the surgical intensive care unit.

OBJECTIVE: To examine the impact of adherence to a ventilator-associated pneumonia (VAP) bundle on the incidence of VAP in our surgical intensive care units (SICUs). DESIGN: Prospectively collected data were retrospectively examined from our Infection Control Committee surveillance database of SICU patients over a 38-month period. Cost of VAP was estimated at $30,000 per patient stay. SETTING: Two SICUs at a tertiary care academic level I trauma center. PATIENTS: Ventilated patients admitted to a SICU. INTERVENTION: The Institute for Healthcare Improvement VAP bundle was instituted at the beginning of the study and included head-of-bed elevation, extubation assessment, sedation break, peptic ulcer prophylaxis, and deep vein thrombosis prophylaxis. A daily checklist was considered compliant if all 5 items were performed for each patient. MAIN OUTCOME MEASURES: Patients were assessed for VAP. Staff were assessed for compliance with the VAP bundle. RESULTS: Prior to initiation of the bundle, VAP was seen at a rate of 10.2 cases/1000 ventilator days. Compliance with the VAP bundle increased over the study period from 53% and 63% to 91% and 81% in each respective SICU. The rate of VAP decreased to 3.4 cases/1000 ventilator days. A cost savings of $1.08 million was estimated. CONCLUSIONS: Initiation of the VAP bundle is associated with a significantly reduced incidence of VAP in patients in the SICU and with cost savings. Initiation of a VAP bundle protocol is an effective method for VAP reduction when compliance is maintained.