Interventions to control nosocomial transmission of SARS-CoV-2: a modelling study

BACKGROUND

Emergence of more transmissible SARS-CoV-2 variants requires more efficient control measures to limit nosocomial transmission and maintain healthcare capacities during pandemic waves. Yet the relative importance of different strategies is unknown.

METHODS

We developed an agent-based model and compared the impact of personal protective equipment (PPE), screening of healthcare workers (HCWs), contact tracing of symptomatic HCWs and restricting HCWs from working in multiple units (HCW cohorting) on nosocomial SARS-CoV-2 transmission. The model was fit on hospital data from the first wave in the Netherlands (February until August 2020) and assumed that HCWs used 90% effective PPE in COVID-19 wards and self-isolated at home for 7 days immediately upon symptom onset. Intervention effects on the effective reproduction number (R_E), HCW absenteeism and the proportion of infected individuals among tested individuals (positivity rate) were estimated for a more transmissible variant.

RESULTS

Introduction of a variant with 56% higher transmissibility increased - all other variables kept constant - R_E from 0.4 to 0.65 (+ 63%) and nosocomial transmissions by 303%, mainly because of more transmissions caused by pre-symptomatic patients and HCWs. Compared to baseline, PPE use in all hospital wards (assuming 90% effectiveness) reduced R_E by 85% and absenteeism by 57%. Screening HCWs every 3 days with perfect test sensitivity reduced R_E by 67%, yielding a maximum test positivity rate of 5%. Screening HCWs every 3 or 7 days assuming time-varying test sensitivities reduced R_E by 9% and 3%, respectively. Contact tracing reduced R_E by at least 32% and achieved higher test positivity rates than screening interventions. HCW cohorting reduced R_E by 5%. Sensitivity analyses show that our findings do not change significantly for 70% PPE effectiveness. For low PPE effectiveness of 50%, PPE use in all wards is less effective than screening every 3 days with perfect sensitivity but still more effective than all other interventions.

CONCLUSIONS

In response to the emergence of more transmissible SARS-CoV-2 variants, PPE use in all hospital wards might still be most effective in preventing nosocomial transmission. Regular screening and contact tracing of HCWs are also effective interventions but critically depend on the sensitivity of the diagnostic test used.

Public health response to two imported, epidemiologically related cases of Lassa fever in the Netherlands (ex Sierra Leone), November 2019

On 20 November 2019, Lassa fever was diagnosed in a physician repatriated from Sierra Leone to the Netherlands. A second physician with suspected Lassa fever, repatriated a few days later from the same healthcare facility, was confirmed infected with Lassa virus on 21 November. Comprehensive contact monitoring involving high- and low-risk contacts proved to be feasible and follow-up of the contacts did not reveal any case of secondary transmission in the Netherlands.

Preparedness and the importance of meeting the needs of healthcare workers: a qualitative study on Ebola

BACKGROUND

Healthcare workers (HCWs) face specific challenges in infectious disease outbreaks, which provide unusual, new events with exposure risk. The fear of infection or new, unknown tasks in an unfamiliar setting, for example, may complicate outbreak management.

AIM

To gain insight into how healthcare organizations can prepare to meet the needs of their HCWs by capturing the experiences of HCWs with patients with suspected Ebola virus disease.

METHODS

We conducted 23 in-depth interviews with HCWs, of whom 20 worked in a Dutch university hospital and three worked in a regional ambulance service. We invited HCWs who cared for patients with suspected Ebola or who were on the team preparing for admission of such patients in the period 2014-2015.

FINDINGS

The HCWs were stressed and anxious, but most rated their overall experience as positive. We categorized the reported experiences in three main themes, namely, experiences related to: (i) the novelty of the threat, (ii) the risk of infection and fear of transmission, and (iii) the excessive attention. Our results underline the importance of a supportive working environment suitable for crises.

CONCLUSION

The experiences of HCWs dealing with patients with suspected Ebola can direct improvements in generic preparedness for highly transmissible diseases.

HPV-related anogenital disease and HIV infection: not always 'ordinary' condylomata acuminata

Human papillomavirus (HPV) is responsible for various diseases in the anogenital region which range from benign condylomata acuminata to anal carcinoma. Buschke-Loewenstein tumour is a clinically 'intermediate' condition which is histologically benign but due to extensive destruction of the local tissues can show malignant behaviour. Its early recognition as a different clinical entity to 'ordinary' condylomata acuminata is important for its adequate management. Immunocompromised persons, such as those with HIV infection, have a higher incidence of HPV-related anogenital disease. Different aspects of the HPV-related anogenital disease in HIV-positive individuals are discussed.

Oerskovia xanthineolytica: a new pathogen in bone marrow transplantation

A 53-year-old woman with non-Hodgkin lymphoma underwent an autologous bone marrow transplant (BMT). Incomplete reconstitution necessitated the use of a long-term central venous catheter. One year after BMT she presented with fever. Echocardiography revealed vegetations on the tricuspid valve. Gram-positive rods grown from blood cultures and catheter tip were identified as Oerskovia xanthineolytica. We report the first case of native valve endocarditis caused by this organism.