The initial search in the four databases resulted in a total of 1251 articles ; after removing duplicates, a total of 983 articles were screened. In detail, according to the title and abstract screening process, 127 articles met pre-defined inclusion criteria, and those were reviewed in full text. Finally, a total of 47 articles were retained. All those articles were available in full text and met inclusion criteria defined and dealt with HSR, focusing on characteristics that can assist healthcare systems to stay resilient in the face of a shock.
A PRISMA flow chart detailing steps of the selection process is reported in Fig. 2.
Descriptive analysis
A descriptive analysis of the main data extracted from the 47 articles retained in the present review was carried out to summarize their characteristics and findings.
Timeline and geographical distribution. The timeline distribution of the papers included in the present study is shown in Fig. 3. Before 2013 only three articles met inclusion criteria defined. The number of papers increased during 2013–2016 and peaked in 2020. Notably, the number of articles for 2021 only accounts for the first half of the year.
As shown in Fig. 4, most of the papers included were from Europe and Africa.
Type of crisis. According to our inclusion criteria, most of the selected papers addressed specific shocks or crises (n = 43; 91%). Some articles used multiple crises to compare and contrast distinct situations and challenges or to justify their framework or model (4, 26). In general, the most commonly addressed crises were infectious disease outbreaks (n = X) and conflicts (n = X). However, other crises, such as natural disasters (n = X), economic crises (n = X), climate change (n = X), terrorist attacks (n = X), and migrations (n = X), were also investigated.
Methodological analysis
Before starting this study, we looked for literature introducing an operational tool to lead the health system toward resilience while exposed to shock. By having this idea about the importance of such a tool, we studied selected articles to find characteristics of health system resilience.
Therefore, by studying 47 selected articles and analyzing them, We identified all the introduced characteristics of health system resilience. Then we grouped them using the concept they had in common. Since there is still no comprehensive system in this subject that includes unified characteristics, different articles have used various terms to express the same concept.We grouped these synonymous terms and reached 53 characteristics for health system resilience.
Eventually, we used seven building blocks ( as explained before) to classify these characteristics for ease of use and reference Table 2.
Leadership and Governance
Leadership and governance were highlighted as critical factors that can improve HSR during a crisis. Governance refers to direct and indirect rules that shape authority, the relationship between actors and sectors, and their responsibilities. Managing the HSR is dependent on the ability to manage the actors, networks, and institutions that have an impact on it by implicit and explicit rules (48). Before and during a shock, the inception, formulation, adoption, implementation, and evaluation of rules and policies, as well as making them explicit for various sectors and actors, are critical responsibilities (29, 31, 33, 38). A surveillance system needs to monitor and control the implementation of these rules to discover and report issues (3, 15). Polycentric governance and multisectoral collaboration are defined as institutional design which helps to foster the resilience (10, 14, 25, 28, 40, 56). Strengthening the system to adapt to a shock or crisis sometimes requires adjustment and modification in resources in the short term without prompting a permanent change in the system structure (42). Therefore, the system should adjust some indicators, capacities, and planning changes (21, 27, 30, 53). In the face of a financial crisis, the healthcare system, for example, had to implement staff reduction strategies. In contrast, during another, such as the Covid-19 pandemic, some healthcare systems were forced to boost their staffing level (31, 36, 47, 57). Sudden shocks often create an additional need for transport, so enhancing the logistic system, and planning could help make the system more resilient (23, 54). During the crisis, equity and transparency are often overlooked, despite the fact that they were emphasized in the literature as fundamental elements of HSR (35, 41). Since the Ebola outbreak, trust has been recognized as an important component of HSR that many scholars and practitioners have considered (8, 43, 44). Another critical component assisting help systems to stay more resilient while exposed to a shock is meaningful community engagement and volunteerism management by assisting with decision-making, planning, design, and delivery of services (26, 32, 55). Developing resilience in health care is sometimes only achievable within a context of solidarity, especially in low-income nations where they can not only rely on internal resources. Therefore in the framework of solidarity, they can use the contribution of more developed countries to strengthen the healthcare system (3, 7, 33, 53).
Financing
Funding and financing are identified as critical criteria enabling or hindering the ability of the healthcare system to respond to a shock. Adequately funded systems can resist shocks better, while discrete financing amplifies the negative impact. So, minimizing the risk of being underfunded affects HSR (22, 34, 54). During a crisis, the demand and consumption of resources typically increase dramatically. Effective use and protection of resources help the system withstand the shock and preserve its performance (22, 28, 34, 40, 41). Additionally, stock-outs may happen due to excessive utilization or delays in procurement that the regular funding plans cannot address. In order to create a more resilient healthcare system and as a key component of preserving health access and service delivery, mobilization of the funds and using diverse financial resources are necessary (39, 42, 45, 49).
Health workforce
When a shock occurs, healthcare staff are often the first responders. Insufficient distribution of human resources in a healthcare organization could cause inefficiency in the system's performance to meet the unexpected needs of an acute crisis. Hence, enhancing resilience and promoting interoperability requires an adequate workforce (3, 27, 53). Past studies mention that while facing a crisis, a healthcare system may have several challenges with human resources. One of the main challenges is related to skill sets. Training and an up-to-dated workforce are needed to improve and develop these skills. Training must address the expanded roles and improve multiple skills that staff members may need (23, 24, 36, 38, 51). Prior research found that providing incentives, material, financial and psychological support for the workforce during and after a crisis is significantly helpful. This is an essential practical help that gives a sense of commitment to staff (3, 25, 31, 42, 47).
Service Delivery
According to the reviewed articles, responding to additional requests for treatment and providing extra services during the shock should not cause any service interruption. Moreover, the treatment should be continuous and maintain the same quality (23, 25, 30, 37, 40, 57). It is obvious that the healthcare system bears an additional burden during crises, resulting in bottlenecks in many sectors. The vulnerable population is also more in danger, and it is often impossible to delay their need for treatment. Establishing orders or prioritization to cut down on delays hence improves organizational performance (4, 7, 15, 45). In various HSR-related studies, it is suggested that health centers use a clear patient pathway to improve communication, boost flow, and decrease risk. The prevalence of the COVID-19 pandemic has brought this trait to broader attention in recent years (7, 29, 36, 39).
Medical Product
Several articles in this review indicate that providing an adequate number of medical products and equipment in the shortest possible time can help the healthcare system to maintain routine care and respond better to shock (25, 27, 31). For instance, the Covid-19 pandemic affected countries most severely when they lacked the necessary infrastructure and medical supplies (35). Resilience relies on accessibility, diversity, and redundancy of resources, and it is also recommended that the healthcare system provides these demands from alternative suppliers. Indeed, dependence on a single provider puts the system at risk since the service may be disrupted if the supplier becomes unavailable (21, 34, 39, 50). While crises have various characteristics, surge capacity, specifically for medical products, is likely to benefit from the learning achieved by the healthcare system as they deal with weak signals such as congestion and anticipate shortages of products in the inventory system (36, 48, 49). Reviewed articles suggest that systems need to have strategic plans and inventory reserves to address increasing demands during insecure periods of crisis and shocks (3, 35, 54, 55).
Information system
The ability of healthcare systems to respond to shocks has been shown to be highly dependent on the health management information system. Different parts of a complex system, such as the health care system, need to be related and collaborate in a homogeneous network to increase situational awareness. For this reason, a continuously reliable system is required to monitor its activities and collect and analyze the related data (14, 36, 45, 58). The potential capacities of healthcare systems to adapt and adjust to a shock can be identified and emerge by effective management of the information system (39, 48). Furthermore, the collected data can be used as a source of information to anticipate possible errors, issues, and challenges that the system may face while exposed to a crisis (37, 46, 58). The system may need different sorts of information during specific shocks compared to regularly required information, which is necessary for operational purposes. Therefore, a resilient healthcare system should be able to have access to information from diverse sources, evaluate the implications of different events, and apply the analysis to operational decisions and policies (10, 30, 37, 49). The health information management system needs to ensure the reliability, quality, and protection of the data (23, 29, 50). Reducing risk and boosting resilience in the face of a shock entails a committed alliance and information sharing. In order to achieve this goal, accessibility to information should be facilitated by an effective and reliable communication infrastructure (32, 51). One characteristic of resilient organizations is their capacity to exploit weak signals, which frequently represent underlying issues affecting the entire system, as chances for learning and improvement. Thus, a resilient healthcare system can continuously use internal data and feedback to improve its performance during shocks (8, 15, 34).
Safety and Immunization
Healthcare service continuity is critically dependent on risk management and control under the mounting pressure of a shock. Therefore, assessing the people's and the facilities' safety is essential (50). It is absolutely necessary to enforce protection for the medical workforce during a crisis when they are often more in danger. Therefore, safety and preventive equipment, as well as immunization technology, must be provided urgently (21, 24, 31, 52, 55). Additionally, the potential gaps in the safety system need to be highlighted by providing guidelines, notification, and training courses and increasing awareness (36, 45, 47).