Scope of the Review

This review was conducted as part of a project commissioned by the Agency for Healthcare Research and Quality (AHRQ; Rockville, Maryland USA) calling for a detailed Technical Brief (Figure 1) on the evidence from studies in the United States on Infection Prevention and Control for the Emergency Medical Services and 9-1-1 Workforce. ^{Reference Jenkins, Hsu and Russell3} The protocol for the Technical Brief is available on AHRQ’s web site. ⁴ This evidence review followed methods consistent with those outlined in the Evidence-Based Practice Center Methods Guidance. ⁵ This article highlights the characteristics and effectiveness of workplace practices and interventions to prevent, recognize, and control infectious diseases.

Figure 1. Conceptual Framework for Infection Prevention and Control in EMS Clinicians.

Abbreviations: EMS, Emergency Medical Services; IPC, infection prevention and control; PPE, personal protective equipment.

Study Selection

Studies in this review targeted EMS clinician populations in the United States and IPC interventions with control groups. This review included but was not limited to the following outcomes: incidence, prevalence, duration, and severity of disease, missed work, vaccine uptake, health care utilization, separation from the workforce, disability, and death from infections. Interventions included but were not limited to training and education, PPE protocols, personnel or staffing changes, budget changes, vaccine clinics or offerings, and equipment availability.

A systematic search for published evidence was conducted using: PubMed (National Center for Biotechnology Information, National Institutes of Health; Bethesda, Maryland USA); Embase (Elsevier; Amsterdam, Netherlands); CINAHL (EBSCO Information Services; Ipswich, Massachusetts USA); and SCOPUS (Elsevier; Amsterdam, Netherlands) from January 1, 2006 through March 15, 2022. The search was limited to studies published since 2006 because it corresponds to passage of the landmark Pandemic and All-Hazards Preparedness Act in 2006, ⁶ which focused on improving the nation’s public health and medical preparedness and response capabilities for emergencies. Complete search strategies are provided in Supplemental Tables 1-4 (Appendix; available online only). Two members from the team independently assessed each citation to determine whether it met inclusion or exclusion criteria (Table 1).

Table 1. Inclusion and Exclusion Criteria

Abbreviations: EMS, Emergency Medical Services; PPE, personal protective equipment.

* Microbes of interest included but are not limited to methicillin-resistant Staphylococcus aureus, severe acute respiratory syndrome coronavirus 2, influenza, tuberculosis, human immunodeficiency virus, and hepatitis B and C.

Data Extraction and Synthesis

For each eligible study, a team member used an Excel spreadsheet (Microsoft Corp.; Redmond, Washington USA) to extract information about the characteristics, effectiveness, and context of interventions, following the framework in Figure 1. To assess effectiveness, data were abstracted on the outcomes of each study, whether there was a statistically significant effect, and the direction and magnitude of the effect with the corresponding 95% confidence intervals (CIs). Sample sizes were also captured. A second team member reviewed extracted information for accuracy.

Paired reviewers independently assessed the quality of each study by focusing primarily on classification of the study design according to the accepted hierarchy of study designs. The quality of studies was assessed using three questions from the Effective Public Health Practice Project tool ^{Reference Thomas, Ciliska and Dobbins7} : (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?

The authors described the characteristics of the included studies and generated evidence maps describing the results using Stata (Intercooled, version 14.2; StataCorp; College Station, Texas USA).

The search yielded 8,730 unique citations (Figure 2). After screening abstracts and full text of articles, 11 studies were included (N = 20,438 participants). ^{Reference Brown, Schwarcz and Counts8–Reference Rebmann, Wright and Anthony18} Five studies were published in 2020 or later (Figure 3). Many of the studies published in 2020 or later assessed the prevalence of COVID-19.

Figure 2. Results of Literature Search.

Abbreviation: EMS, Emergency Medical Services.

*Articles could be excluded for more than one reason.

Figure 3. Number of Studies Included by Year of Publication.

Study Quality

Eleven (11) studies were identified as addressing the effectiveness of IPC interventions in EMS clinicians. ^{Reference Brown, Schwarcz and Counts8–Reference Rebmann, Wright and Anthony18} All studies were observational studies with a concurrent comparison group; nine studies were prospective cohorts ^{Reference Grant, Harrison and Nuñez10–Reference Rebmann, Wright and Anthony18} and two were retrospective cohorts. ^{Reference Brown, Schwarcz and Counts8,Reference Glaser, Chui and Webber9} Six were in urban settings^{,Reference Glaser, Chui and Webber9,Reference Grant, Harrison and Nuñez10,Reference Halbrook, Gadoth and Martin-Blais12,Reference Miramonti, Rinkle and Iden15,Reference Newberry, Gautreau and Staats16,Reference Rebmann, Wright and Anthony18} and five were in multiple settings. ^{Reference Brown, Schwarcz and Counts8,Reference Gregory, Powell and MacEwan11,Reference Harris and Nicolai13,Reference Hubble, Zontek and Richards14,Reference Orellana, Hoet and Bell17} The studies took place in eight different states. Although few listed a jurisdictional funding description, a post-publication analysis of the jurisdictions suggests that studies were funded by a mixture of fire and third service (ie, stand-alone ambulance) departments. Seven studies included both EMS workers and firefighters involved in medical care ^{Reference Brown, Schwarcz and Counts8–Reference Grant, Harrison and Nuñez10,Reference Halbrook, Gadoth and Martin-Blais12,Reference Harris and Nicolai13,Reference Newberry, Gautreau and Staats16,Reference Rebmann, Wright and Anthony18} and four studies only focused on EMS workers. ^{Reference Gregory, Powell and MacEwan11,Reference Hubble, Zontek and Richards14,Reference Miramonti, Rinkle and Iden15,Reference Orellana, Hoet and Bell17} The total study sample size ranged from 186 to 10,612 EMS and 9-1-1 workers.

None of the studies used an experimental study design. According to the inclusion criteria for this review, all 11 of the included studies had a concurrent comparison group. Although all studies were somewhat or very likely to include workers representative of the target population, only 27% of the studies reported a participation rate of 80% or higher among those invited to participate (Table 2). Regarding potential selection bias, only three studies presented data indicating no important differences between those who participated and those who did not, while one study reported important differences between groups (Table 2). The other seven studies did not present enough information to assess selection bias.

Table 2. Quality of Studies that Reported on the Characteristics and Effectiveness of EMS Practices to Prevent, Recognize, and Control Infectious Diseases

Abbreviation: EMS, Emergency Medical Services.

Figure 4 presents an evidence map of the main characteristics of the IPC practices that have been studied in EMS clinicians, and whether they reported on how practices vary by demographic, workforce, and practice characteristics. Each circle represents the number of studies, with vaccine uptake for influenza being the most frequently reported type of IPC practice. Only one study focused on prevention of needlestick injuries. Two studies focused on standard precautions for IPC.

Figure 4. Evidence Map of the Studies that Report on Infection Prevention and Control Practices and How they Vary by Demographic, Workforce, and Practice Characteristics.

Note: Each study is represented by a circle. The size of the circle is proportional to the sample size.

Eight studies reported on the effectiveness of interventions preventing infectious diseases among the EMS and 9-1-1 workforce. ^{Reference Brown, Schwarcz and Counts8,Reference Glaser, Chui and Webber9,Reference Harris and Nicolai13–Reference Rebmann, Wright and Anthony18} The studies were heterogeneous, involving five distinct types of IPC practices and focusing on four different infectious diseases. The studies were so different from each other that it would not be appropriate to perform any meta-analysis. Figure 5 demonstrates an evidence map of studies reporting on the effectiveness of IPC practices in EMS clinicians. The most common infectious disease studied was influenza. On-site vaccine clinics were the most commonly studied workforce practice.

Figure 5. Evidence Map of Studies Reporting on the Effectiveness of IPC Practices in Emergency Medical Service Clinicians.

Note: Each study is represented by a circle. The size of the circle is proportional to the sample size.

Abbreviations: IPC, infection practice and control; AGP, aerosol-generating procedures; MRSA, methicillin-resistant Staphylococcus aureus; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.

Standard Precautions and PPE

Harris found significant differences in protective practices among Advanced Life Support (ALS) and Basic Life Support (BLS) certified/licensed EMS workers. ^{Reference Harris and Nicolai13} Specifically, ALS-certified/licensed EMS workers were more likely than BLS-certified/licensed EMS workers to wear gloves for all calls (unadjusted odds ratio [OR] 1.75; 95% confidence interval [CI], 0.81 to 3.79), use face masks (unadjusted OR 4.86; 95% CI, 1.44 to 16.4), and use protective devices during resuscitation (unadjusted OR 17.3; 95% CI, 1.04 to 28.8). Increased use of standard precautions ¹⁹ such as face masks, gloves, and protective devices for resuscitation were associated with a decreased likelihood of a needlestick.

Grant described higher selected self-reported PPE use among firefighters/paramedics, such as for gloves, N-95 respirators, and eye protection, on medical versus non-medical runs. ^{Reference Grant, Harrison and Nuñez10} The study further detailed self-reported PPE use among firefighters/paramedics before versus after a Department of Public Health shelter-in-place order. ^{Reference Grant, Harrison and Nuñez10} On non-medical runs, use of individual PPE measures increased significantly after the shelter-in-place order (P <.0001 for surgical masks, N-95 respirators, eye protection, and gowns; P <.05 for gloves), while self-reported use of “no PPE” decreased significantly (P <.0001). On medical runs, use of individual PPE increased significantly after the shelter-in-place order (P <.0001 for surgical masks, N-95 respirators, eye protection, and gowns), while self-reported use of “no PPE” did not differ before versus after the shelter-in-place order.

Three studies reported on effectiveness of protective equipment and behaviors in preventing and controlling infectious disease. ^{Reference Harris and Nicolai13,Reference Newberry, Gautreau and Staats16,Reference Orellana, Hoet and Bell17} Newberry found that lack of PPE or PPE breach were correlated with higher SARS-CoV-2 seropositivity (unadjusted risk ratio [RR] 4.2; 95% CI, 1.03 to 17.22). ^{Reference Newberry, Gautreau and Staats16} Orellana found that less frequent daily handwashing (survey-weight adjusted OR 4.20; 95% CI, 1.02 to 17.27) and less frequent hand hygiene after glove use (survey-weight adjusted OR 10.51; 95% CI, 2.54 to 43.45) were positively correlated with nasal colonization of Methicillin-resistant Staphylococcus aureus (MRSA). ^{Reference Orellana, Hoet and Bell17} Harris found that disposing of other contaminated materials was significantly associated with decreased needle stick injuries (unadjusted OR 0.2; 95% CI, 0.06 to 0.64). ^{Reference Harris and Nicolai13}

In 2021, Brown reported on the association between aerosol-generating procedures (AGPs) with full PPE (defined as a mask, eye protection, gloves, and a gown) and SARS-CoV-2 diagnoses (unadjusted incidence rate ratio [IRR] 1.64; 95% CI, 0.22 to 12.26). ⁵ However, these data are based on only one EMS clinician developing COVID-19 infection in the cohort studied out of 182 total AGPs performed and 8,582 person-days at risk while in PPE and performing an AGP.

Vaccinations and Policies

The Glaser study ^{Reference Glaser, Chui and Webber9} found that vaccination was less likely in those younger than 30 years old (adjusted OR 0.70; 95% CI, 0.62 to 0.78), African Americans (adjusted OR 0.46; 95% CI, 0.40 to 0.50), and Hispanics (adjusted OR 0.87; 95% CI, 0.77 to 0.99) after adjusting for age, gender, race, class (EMS versus firefighter), and smoking status. Gregory, in 2021, reported on odds of COVID-19 vaccinations by associations with age (referent <38 years; 39 to 50 years: 1.56, 95% CI, 1.17 to 2.08; >51 years: 2.22, 95% CI, 1.64 to 3.01) and male sex (1.26, 95% CI, 1.01 to 1.58). ^{Reference Gregory, Powell and MacEwan11}

Hubble, in 2011, found that EMS professionals in rural areas (35.5%) received the influenza vaccine at lower rates than urban (50.0%) or suburban (54.3%) EMS professionals (unadjusted P = .01). ^{Reference Hubble, Zontek and Richards14} Gregory, in 2021, found that increased COVID-19 vaccination uptake was associated with residing in an urban/suburban area (referent rural; 1.36, 95% CI, 1.08 to 1.70) and advanced education (referent General Educational Development or high school and below; bachelor’s and above: 1.72, 95% CI, 1.19 to 2.47). ^{Reference Gregory, Powell and MacEwan11} In this study, despite availability of vaccine, 69.8% of EMS professionals reported having received a COVID-19 vaccine while 30.2% indicated that they had not. ^{Reference Gregory, Powell and MacEwan11}

In 2021, Halbrook found that COVID-19 vaccine uptake was higher among in-hospital health care workers (96.0%) compared to EMS workers (87.5%) and that EMS workers were significantly more likely to delay receiving a vaccine (adjusted OR 2.94; 95% CI, 1.71 to 5.04 after adjusting for age, sex, race, education, and patient contact). ^{Reference Halbrook, Gadoth and Martin-Blais12} Gregory found increased odds of COVID-19 vaccination were associated with hospital-based systems (referent fire-based agency; 1.53, 95% CI, 1.04 to 2.24). ^{Reference Gregory, Powell and MacEwan11}

Rebmann, in 2012, found that mandatory vaccine policies for H1N1 and other strains of influenza increased the vaccine uptake rates; 100% of participants reporting mandatory vaccine policies also reported being vaccinated while those who did not have a mandatory vaccine policy reported a 66.8% vaccination rate for H1N1 influenza (unadjusted P <.01) and a 75.6% vaccination rate for seasonal influenza (unadjusted P <.001). ^{Reference Rebmann, Wright and Anthony18} Emergency medical technicians whose employer had a mandatory vaccination policy were significantly more likely to receive the seasonal influenza vaccine (100.0% versus 75.6%) or the H1N1 influenza vaccine (100.0% versus 66.8%) compared with those without such a policy (unadjusted P <.001 and P <.01, respectively). ^{Reference Rebmann, Wright and Anthony18}

Two studies reported on the effectiveness of vaccine clinics at the work site. ^{Reference Glaser, Chui and Webber9,Reference Hubble, Zontek and Richards14} Hubble found that workers were more likely to be vaccinated against influenza if they recalled their employer offering the flu vaccine (unadjusted OR 3.3; 95% CI, 1.3 to 8.3) and if they received training or education from their employer on the flu vaccine or influenza illness (unadjusted OR 1.5; 95% CI, 1.2 to 2.1). ^{Reference Hubble, Zontek and Richards14} Workers were more likely to be accepting of a vaccine during an on-site vaccine clinic when surrounded by their peers who were also receiving the vaccine. In addition, the authors noted that supervisor and peer buy-in was a factor during the vaccine clinics. In a study by Glaser, the acceptance rate of the H1N1 influenza vaccination was 57.2% (5,746 out of 9,559) during a targeted, active, and dedicated vaccine program in a bio-preparedness drill as compared to 34.4% (362 out of 1,053) during medical visits. ^{Reference Glaser, Chui and Webber9} During the bio-preparedness drill, the EMS workers and firefighters also received targeted education.