Key Points Question What are the risk factors for the acquisition of methicillin-susceptible Staphylococcus aureus (MSSA) colonization and infections in a neonatal intensive care unit? Findings In this cohort study of 590 newborns, the acquisition of S aureus colonization and infection was monitored until hospital discharge. Colonization with MSSA was associated with lower birth weight, longer hospitalization, and higher odds of acquiring S aureus infection during hospitalization. Meaning These findings suggest that nasal colonization is a relevant risk factor for MSSA infection in a nonoutbreak neonatal intensive care unit setting.

Mathematical models in epidemiology are an indispensable tool to determine the dynamics and important characteristics of infectious diseases. Apart from their scientific merit, these models are often used to inform political decisions and interventional measures during an ongoing outbreak. However, reliably inferring the epidemical dynamics by connecting complex models to real data is still hard and requires either laborious manual parameter fitting or expensive optimization methods which have to be repeated from scratch for every application of a given model. In this work, we address this problem with a novel combination of epidemiological modeling with specialized neural networks. Our approach entails two computational phases: In an initial training phase, a mathematical model describing the epidemic is used as a coach for a neural network, which acquires global knowledge about the full range of possible disease dynamics. In the subsequent inference phase, the trained neural network processes the observed data of an actual outbreak and infers the parameters of the model in order to realistically reproduce the observed dynamics and reliably predict future progression. With its flexible framework, our simulation-based approach is applicable to a variety of epidemiological models. Moreover, since our method is fully Bayesian, it is designed to incorporate all available prior knowledge about plausible parameter values and returns complete joint posterior distributions over these parameters. Application of our method to the early Covid-19 outbreak phase in Germany demonstrates that we are able to obtain reliable probabilistic estimates for important disease characteristics, such as generation time, fraction of undetected infections, likelihood of transmission before symptom onset, and reporting delays using a very moderate amount of real-world observations.

Conflicting evidence surrounding SARS-CoV-2 transmission, particularly airborne transmission, may have contributed to heterogeneous recommendations for respiratory protection across countries and organizations. 1 Variability among guidelines may generate confusion, anxiety, and mistrust among health care professionals (HCPs) regarding the ability of respiratory protection to prevent SARS-CoV-2 transmission. We assessed variation in international and national guidelines on respiratory protection for HCPs in hospital settings during the first year of the COVID-19 pandemic. MethodsThe Nantes University Hospital determined that this systematic review was exempt from formal review by the institutional review board and from written informed consent because this study used publicly accessible documents. We followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline. Infection prevention and control guidelines on respiratory protection for HCPs published from January 1 to December 31, 2020, by leading organizations in 4 countries and 2 international organizations were collected through a monthly consultation of their official websites (eMethods in the Supplement). We defined HCPs as all workers employed by a hospital. For each included guideline, we extracted data regarding the organization, date of publication, type of respiratory protection recommended (ie, medical face mask [MF] or respirator, including N95 or N99 or filtering facepiece [FFP2 or FFP3]), indication for use, and lists of aerosol-generating procedures (AGPs). We classified the indications for respirators as recommended during AGPs, recommended for targeted continuous use in high-risk areas, and recommended during contact with individuals with suspected or confirmed infections in any circumstance. The indications for MFs were categorized as universal face masking recommended, targeted continuous face masking recommended, or recommended during contact with individuals with suspected or confirmed infections only. Targeted continuous use was defined as the wearing of a respirator or MF by all HCPs during their entire shifts in clinical areas with patients with or without COVID-19.Universal face masking was defined as a requirement for all HCPs entering the facility to wear an MF.