Methods

Discussions With Key Informants

In consultation with representatives from the Agency for Healthcare Research and Quality (AHRQ) and National Highway Traffic Safety Administration (NHTSA), we recruited a panel of external experts on emergency medical services (EMS) clinicians, state-level EMS leadership, and programs relevant to EMS and 911 workers. We also engaged representatives of professional societies in infectious diseases and emergency medicine: National Registry of Emergency Medical Technicians (NREMT), National Association of EMS Physicians, National Association of State EMS Officials, National Association of State 911 Administrators, National Association for Public Safety Infection Control Officers, and the Centers for Disease Control and Prevention (including the CDC’s National Institute for Occupational Safety and Health). The external experts provided advice on how we answered each of our Guiding Questions (GQs). Questions for the Key Informants included: (1) do they suggest any revision in our analytic framework? (2) do they suggest any revision in how we define the relevant scope of occupational exposures to infection? (3) do they suggest any change in the criteria we use to determine whether an intervention is effective? (4) do they suggest any change in how we define or describe relevant contextual factors? (5) what do they think is most important to know about the quality of the studies we identify? (6) how important is it to determine the seroprevalence or infection rates of EMS workers if there is no comparison group? and (7) what is the value of studies that assess the infectious state of equipment?

Published Literature Search

We conducted a systematic search for published evidence using PubMed^®, Embase^®, CINAHL^®, and SCOPUS from January 1, 2006, to March 15, 2022. We limited the search to the last 15 years. A 15-year cut-off corresponds to passage of the landmark Pandemic and All-Hazards Preparedness Act (PAHPA) in 2006,⁹ which focused on improving the nation’s public health and medical preparedness and response capabilities for emergencies. Our search strategies are in Appendix A.

Two members from the team independently assessed each citation to determine whether it met inclusion criteria (Table 1). Team members had expertise in emergency medicine, emergency medical services, infection control, or evidence synthesis. We included studies regardless of study quality if they provided original data on the GQs.

Table 1

Inclusion and exclusion criteria.

Gray Literature Search

We searched the gray literature for reports from selected state and federal government agencies and nongovernmental organizations that have an interest in this topic (e.g., CDC, the National Institutes of Health, Infectious Diseases Society of America, the Assistant Secretary for Preparedness and Response (ASPR), Society for Healthcare Epidemiology of America, and Association for Professionals in Infection Control and Epidemiology). We searched for ongoing research by using the clinicaltrials.gov database and by querying our advisors. We reviewed any material that was submitted through the Supplemental Evidence and Data for Systematic Reviews portal.

Information Management

For each eligible study, a team member used an Excel spreadsheet to extract information about the epidemiologic characteristics of the infectious disease exposures (GQ 1), as well as characteristics, effectiveness, and context of interventions (GQs 2-3), following the framework in Figure 1. We used the metaprop command in Stata to calculate 95% confidence intervals (CIs) associated with reported incidence and prevalence rates (and rates of serious infections). To assess effectiveness, we abstracted data on the main outcomes of each study, whether there was a statistically significant effect, and the direction and magnitude of the effect with the corresponding 95% CIs. We also captured the sample size of studies, recognizing that some studies may fail to find a significant difference because of a small sample size. A second team member reviewed extracted information for accuracy. For GQ 4, we included a summary of national, state, or local infection prevention and control (IPC) protocols pertinent to the EMS and 911 workforces that were identified in the included studies.

Paired reviewers independently assessed the quality of each study by focusing primarily on classifying the study design according to the accepted hierarchy of study designs. For studies that addressed GQ 1, we also assessed the quality of studies in terms of representativeness, completeness, and accuracy by asking three questions: (1) Are the targeted individuals likely to be representative of the target population? (2) What percentage of targeted individuals agreed to participate? and (3) Did the study report any data on the validity of the tests of interest? To assess the quality of studies that applied to GQs 2-3, we used three questions from the Effective Public Health Practice Project tool:¹⁰ (1) Are the individuals selected to participate in the study likely to be representative of the targeted population? (2) What percentage of selected individuals agreed to participate? and (3) Were there important differences between groups prior to the intervention?

Data Presentation

We used tables and accompanying text to summarize information from the studies on each of the GQs. We created an evidence map with associated data visualization techniques to help describe the extent of the literature on each of the questions. We used the population, intervention, comparison, outcome, timing, setting, and study design (PICOTS) framework to identify and organize the research gaps.

Peer Review and Public Commentary

Experts in emergency medical services and infection control, and individuals representing stakeholder and user communities were invited to provide external peer review of this Technical Brief. AHRQ and an associate editor also provided comments. The draft report was posted on the AHRQ website for 4 weeks to elicit public comment. We addressed all reviewer comments, revising the text as appropriate, and documented everything in a disposition of comments report that will be made available 3 months after AHRQ posts the final Technical Brief on the Effective Health Care website.