Immunization of healthcare personnel: A continuing issue.

Despite the availability of safe and effective vaccines for several decades, outbreaks of vaccine-preventable diseases (VPDs) still occur in healthcare facilities leading to serious morbidity, mortality, and costs. Healthcare personnel (HCP) have long been identified as a high-risk group for occupational exposure to VPDs [1]. At the same time, HCP have been sources of VPDs to susceptible patients [2]. Vaccination constitutes a key measure to protect both HCP and their patients - especially for those who cannot mount good immunologic responses and those with contraindications to vaccines. Beyond protection, immunization of HCP is justified to protect healthcare services from outbreaks, absenteeism, and presenteism. Increasingly immunizations of HCP are being integrated into preparedness and response plans to increase healthcare response capacity for future health threats [3].

In 2014 we were honored to serve as Editors of a special issue dedicated to the vaccination of HCP [4]. Since then, healthcare facilities have been faced with multiple infectious disease health crises of global importance, including the unprecedented Ebola epidemics in West Africa, measles epidemics in many countries, and the COVID-19 pandemic. Despite differences in transmission dynamics and fatality rates, these health crises had a common denominator: HCP have been disproportionately affected [5], [6], [7]. The deaths of HCP from Ebola in Sierra Leone reduced the health workforce by 6.9% which significantly reversed the performance of healthcare services [6], [8]. However, while Ebola vaccine became available few years after the initial West Africa epidemics [9], [10], the past decade thousands of unvaccinated or incompletely vaccinated HCP were infected with measles, often with prolonged morbidity and complications, despite insisting recommendations for measles vaccination [7], [11]. Similarly, safe and effective COVID-19 vaccines were deployed within less than one year after the declaration of the pandemic. Yet, on May 24, 2021 the Director General of the World Health Organization announced at least 115,000 deaths from COVID-19 among HCP globally with a range between 80,000–180,000 deaths [12].

Vaccine hesitancy was declared as one of the top ten threats to global health by the World Health Organization in 2019 [13]. Skepticism and rejection of COVID-19 vaccination among HCP and the public emerged as a major public health issue since the release of the first COVID-19 vaccines in 2020 [14]. In the United States alone, as of September 15, 2021, 30% of HCP in hospitals were still unvaccinated [15]. A recent study demonstrated that COVID-19 vaccination of HCP significantly reduces absenteeism [16]. In light of the continuing surges of healthcare demand and hospitalizations, several countries adopted mandatory COVID-19 vaccination policies for HCP as a prerequisite for employment and most likely others will follow [17], [18], [19], [20], [21]. Moreover, studies from many countries consistently indicate low influenza vaccination rates and significant immunity gaps against many VPDs (e.g., up to 17% for measles, up to 25% for mumps, up to 18.6% for rubella, up to 16.7% for varicella, and up to 35% for hepatitis B) among HCP, despite long-standing vaccination recommendations [1], [22], [23].

The available evidence is clear and indicates that there is no single intervention other than vaccine mandates to achieve persistently high vaccination rates against influenza and other VPDs among HCP [24], [25]. Immunization of HCP is even more imperative and taken on greater urgency as global vaccination coverage rates have dropped the past two years due to disruption of vaccination services [26].

The issue of vaccination policies and vaccinations in general is not an issue of regulations only. Vaccination behavior and decision-making are shaped through childhood and adolescence [27]. In the rapidly evolving scientific landscape of the past two years, vaccination behavior studies have lagged behind the rapid development of COVID-19 vaccines. It is highly likely that the COVID-19 pandemic will influence vaccination perceptions for millions of people over the coming decades - including HCP. Transparency, trust, and ethics in policy-making also influence attitudes towards vaccinations [28]. Cognitive decision-making styles are also critical and should be addressed early in the professional training of HCP [29], [30], [31], [32], [33]. Working within the cognitive structure and cognitive styles of HCP trainees is critical in assisting them in gaining awareness of how they themselves take in and process information, as well as in understanding how their preferred cognitive style(s) is utilized in understanding the scientific method and research/data. Because of this, academic institutions would be wise to incorporate the Preferred Cognitive Styles and Decision Making Model (PCSDM) [30] throughout the HCPs training. The PCSDM [30] can aid not only the individual HCP in understanding their own decision-making and the decision-making strategies of their patients, but this model can also help to guide communication and information intake and processing throughout a HCP educational system (undergraduate, medical school, residency, and continuing medical education). Simply garnering and producing data and facts to patients (the analytical type) alone, while ignoring other cognitive styles, will lead to a deficit in the ability to understand and address other cognitive styles. Multiple strategies for addressing different common cognitive styles, along with examples of how a HCP might hear that cognitive style articulated and strategies to engage in conversation with that cognitive style, are available [34]. Support by healthcare administrations and scientific societies is also required to make immunization of HCP a normative expectation and ethical duty among those who care for vulnerable patients. The COVID-19 pandemic has also revealed the importance of political commitment.

Below we present a brief agenda outline for an evidence-based, holistic approach to achieving high rates of vaccine coverage among HCPs:

Sound vaccination programs that recognize priorities, holistic approach, and the need to protect HCP and the vulnerable patients they serve

Vaccination policies that are based on the appropriate regulatory frame based on ethical and moral duty

Financial and logistic issues should be solved

National vaccination registries are need to follow coverage rates in real-time

Address vaccine hesitancy and cognitive issues early in professional training

Realistic, simplified communication of the expected benefits and risks of vaccines

Codify the above in systems, rules, and expectations that all eligible HCP must be immunized against VPDs for which safe and effective vaccines exist.

We present this collection of articles as a tribute to HCP, and especially those working in frontline roles during these challenging times. We are thankful to colleagues from academia, healthcare, and public health, who joined efforts with the hope of improving vaccination of HCP.

CRediT authorship contribution statement

Helena C. Maltezou: Conceptualization, Writing – original draft. Gregory A. Poland: Conceptualization. Caroline M. Poland: Conceptualization, contribution to writing.

Declaration of Competing Interest

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [Dr. Gregory A. Poland is the chair of a Safety Evaluation Committee for novel investigational vaccine trials being conducted by Merck Research Laboratories. Dr. Poland provides consultative advice on vaccine development to Merck & Co., Medicago, GlaxoSmithKline, Sanofi Pasteur, Johnson & Johnson/Janssen Global Services LLC, Emergent Biosolutions, Dynavax, Genentech, Eli Lilly and Company, Kentucky Bioprocessing, Bavarian Nordic, AstraZeneca, Exelixis, Regeneron, Janssen, Vyriad, Moderna, and Genevant Sciences, Inc. These activities have been reviewed by the Mayo Clinic Conflict of Interest Review Board and are conducted in compliance with Mayo Clinic Conflict of Interest policies. Dr. Poland holds patents related to vaccinia, influenza, and measles peptide vaccines. Dr. Poland has received grant funding from ICW Ventures for preclinical studies on a peptide based COVID-19 vaccine. This research has been reviewed by the Mayo Clinic Conflict of Interest Review Board and was conducted in compliance with Mayo Clinic Conflict of Interest policies.

Caroline M. Poland provides consultative advice to Sanofi Pasteur.

Helena C. Maltezou has no conflict of interest to declare.