Amid the ongoing COVID-19 pandemic and the lack of effective curative treatments, mass vaccination is perceived as the only effective strategy to control the pandemic and reduce its global impact on individuals and societies. Different types of COVID-19 vaccines have been developed so far, using different techniques including mRNA, adenovirus vector, adjuvanted protein, or live-attenuated or inactivated virus vaccines. The current evidence supports the efficacy of the majority of the commercialized and recommended vaccines in eliciting robust production of neutralizing antibodies in the short- and median-term, correlating with a significant reduction in the incidence of COVID-19 infection both in the clinical trial and real life (1–4).

As of February 2022, the number of vaccine doses that have been administered globally was estimated at more than 10 billion, with nearly 60% of the world's population being fully vaccinated (5). However, there is a great discrepancy in vaccination rates between the industrialized countries such as Canada (212.6 doses per 100 population), the United Kingdom (205 doses per 100 population), and the European countries, and developing and low-income countries such as Algeria (31.1 doses per 100 population), Egypt (69.7 doses per 100 population), and Sudan (13.0 doses per 100 population) (5, 6). The COVID-19 Vaccines Global Access (COVAX) initiative's campaign efforts to finance and distribute the vaccine in poor countries are limited by multiple factors including the difficulty of providing all the needs of these countries and the limited funding sources (7). On the other hand, the recent emergence and spread of novel viral variants, notably the B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma), B.1.617 (Delta), B.1.617.2 (Delta-plus), B.1.525 (Eta), B.1.429 (Epsilon), and B.1.1.529 (Omicron) variants compromised the forecasted transition, in the short run, to the pre-pandemic normal life (8–12). As a consequence, the resolution of the issue depends on a three-fold concern, including the success of the global mass immunization, the long-term efficacy of the vaccines, and the dreaded scenario of resistance of the emerging variants to the vaccine-induced immunity (13–15).

In addressing the determinants of success for this global strategy, people's engagement to local vaccination campaigns constitutes a major determinant, besides the adherence to prevention policies and recommendations. Although the modern experience with mass vaccination proved to be effective in controlling and eradicating outbreaks such as Polio, Smallpox, and other diseases (16), vaccine hesitancy has long been identified as one of the major threats facing global health (17–19). Due to several factors, the COVID-19 vaccine is subject to recurrent popular misconceptions and uncertainties, which constitutes further barriers to public adherence to the vaccination strategy (20). Such misconceptions are reported to be particularly prevalent in developing countries and conservative societies, associated with high rates of vaccine hesitancy (21). Consequently, substantial discrepancies have been observed in vaccine acceptance rates across the different regions and cultures (22), with remarkably higher vaccine hesitancy in Eastern Europe, North Africa, the Middle-East, and Central Asia (23).

In Algeria, the largest African country and the 9th country in Africa in terms of population size, the fight against the virus has gone through successive phases since the first confirmed case was declared on February 25, 2020. Since the early phase of the pandemic, the Algerian government opted for broad travel cancellations combined with the intermittent implementation of restrictive and semi-restrictive measures locally, in addition to the deployment of tremendous healthcare resources to treat the infected population (24–26). As of 21 May 2021, date of start of the current study, the country has recorded 126,434 confirmed cases and 3,405 deaths (27). In March 2022, date of last revision of the paper, these figures have doubled with 265,346 confirmed cases and 6,860 deaths (28). The national vaccination campaign started by the end of January 2021 and the current local policy targets all vulnerable groups. However, the vaccination rate remains remarkably low, reaching only 2.5 million doses by 14 July 2021, which represented a coverage rate estimated at 5.8% of the population (6, 29). To date, i.e., 10 March 2022, the coverage rate remains low with only 15% of the population being fully vaccinated (28). This represents a concern, contrasting with the country's efforts to promote the vaccination.

In an attempt to explain this low vaccination rate, the present study was designed to evaluate the levels of engagement among Algerians toward the COVID-19 vaccine and to analyze the associated sociodemographic factors. Additionally, it explored the associated misconceptions and eventual barriers and enablers of vaccine acceptance. Such data would assist the decision-makers in implementing strategic amendments on the vaccination policy and the related communication approaches. We further conducted a systematic review on vaccine acceptance in the Arab countries of the Middle-East and North African (MENA) region.

This is the first nationwide study addressing the Algerian population's attitude toward the COVID-19 vaccine. Using a multidimensional model to measure the likelihood of engagement to vaccination, our study revealed that only 34% of the participants would be engaged to receive the COVID-19 vaccines. The Adjusted regression analysis demonstrated multiple predictors for non-engagement, including female gender, and low/intermediate levels of adherence to preventive measures, whereas a high perception of the disease severity and fear of being infected predicted vaccine acceptance. Additionally, the systematic review findings suggested that Algeria had the lowest vaccine acceptance rate in comparison with other MENA countries, where acceptance rates ranged from 37.4% in Jordan (39) and 75% in the UAE (32). More recent data showed greater disparity in vaccine acceptance rates in the MENA region (23). In comparison with Europe, the lowest acceptance rate of 53.7%, reported in Italy (40), was relatively higher than the acceptance rate observed in our study.

The high perceived severity of COVID-19 was among the independent risk factors for engagement; however, only 25.8% of participants perceived the disease to be severe. Regardless of the acceptability of the vaccine, the severity of the disease will affect the vaccination intention. Perception about the disease severity may be assimilated to a personal opinion or belief regarding the level of hazard or exposure to the crisis and the extent of its adverse impact on the individual (41). In the case of COVID-19, but not specifically, the risk perception may change over time and is further determined by the individual's awareness about and interpretation of the relationship between the virus/pandemic and the observed undesirable effects—and such interpretation may be biased or distorted by other opinions, (mis)beliefs and (mis)conceptions. A theoretical approach by Cori et al. (42), suggested that both risk perception and fear of COVID-19 are determined by cognitive factors, and the author mentioned four key factors including knowledge about the disease/virus, visibility of the risk, trust in the authorities, and healthcare institutions, and voluntary exposure to the virus/infection. The aforementioned factors may be modified by means of awareness-raising campaigns and authoritarian corrective or restrictive measures, aiming at enhancing the risk perception and ultimately increasing the vaccination rates. Evidence from previous data suggests that risk perception about COVID-19 increased in the lockdown phase and decreased in the re-opening phases (43), which was positively associated with the change in vaccine acceptance rate. At the time when the present study was conducted, the country was in a post-re-opening phase, which may explain the low engagement rates observed. Another longitudinal study from the US assessed the trend of people's attitude toward the vaccine, between March and August 2020, and showed heterogeneous results with perceived severity of the disease being one of the determinants of the vaccine acceptance. Furthermore, the authors demonstrated that the trends in both risk perception and vaccine acceptance were likely to be determined by the individual's specific political positions and exposure to media (44). Such observation supports the importance of correcting the cognitive and behavioral factors at the population's level to enhance vaccine uptake.

Similar to other reports from the MENA region, including Kuwait (33), Qatar (35), KSA (34), and Jordan (39), men were more likely to accept the Covid-19 vaccine in Algeria. This can be explained by the increased severity of the disease among men and the higher mortality reported in the majority of countries (45, 46). This statement was extensively mediatized and may have played a role in men's motive to vaccination, developing a relatively more positive attitude toward the vaccine. While such an explanation requires further evidence, notably the associated levels of awareness about the specific health risks on males, other factors may explain the less negative attitude among males that was found in the present study. Among these factors, the impact of the pandemic and restrictive measures on incomes and businesses, which may be more perceived by males in some societies. This explanation may be in line with the significant association of vaccine engagement with being married and having children that were found in the unadjusted analysis in the present study. Another potential factor explaining this gender disparity is the belief that COVID-19 is part of a global conspiracy, which was reportedly more common in women, thus explaining the higher vaccine hesitancy of females in some populations (21, 47).

However, past research data showed conflicting results about gender. A global survey including 13,426 individuals in 19 countries with a high COVID-19 burden showed that men were relatively less likely to have a positive attitude toward vaccination than women (48). Another study showed that women in Russia and Germany had higher acceptance rates of the COVID-19 vaccines than men (49). This phenomenon has been named “the Covid-19 gender paradox” (50). This gender difference can be explained by multidimensional psychological, social, cultural, and environmental influences. Further research may be required to determine the gender-specific factors associated with acceptance or refusal of the vaccine, which would enable designing targeted awareness campaigns with gender-specific messages to enhance the vaccine acceptance rates in both genders.

There is a remarkable similarity between the engagement rates of the general population (35%) and healthcare workers (38%) in the present study, which is an issue of big concern as it may constitute a significant barrier to the national vaccine campaign. Indeed, the practitioner's vaccine hesitancy influences the vaccination attitudes of the patients (51). When providers are unsure of the safety of the vaccine, they are unable to recommend it to the general population. Such an issue should be considered at the critical level by the health authorities, and corrective measures are warranted urgently to increase awareness among health providers. Furthermore, this study showed comparable patterns of safety concerns about the vaccine in the two subgroups, i.e., health workers vs. the general population (75% and 73%, respectively). This indicates the consistency of the popular misconceptions about the COVID-19 vaccine across all categories of the studied population and highlights the need for a comprehensive awareness-raising campaign at the national scale.

Other notable factors of vaccine refusal include fear of the side effects and concern about the efficiency of the vaccines. Similar concerns have been reported in other countries such as Jordan (39, 52) and the USA (52). Arguably, these concerns may be comprehensible, considering the rapid vaccine development process, the novelty of the mRNA technology used in some vaccines, and the public mediatization of the vaccine side effects; all exposing the population to massive misinformation notably in the social media (53, 54). This could be related to the decreasing acceptance rate over time in the MENA region as shown in the systematic review part of the study. Hence there is a crucial need to implement effective strategies to correct the popular misconceptions regarding the vaccine's safety.

This study also highlighted the positive association between the level of adherence to preventive measures and vaccine acceptability. This observation is in accordance with another MENA region study in Kuwait (33), reporting that high adherence to the governmental recommendations was an important predictor for vaccine uptake. Both low adherence to preventive measures and adverse attitudes toward vaccines could reflect adherence to the conspiracy theory, and this was observed among 23.4% of the avoidant group. Conspiracy theories have been associated with vaccine hesitancy as a result of mistrust between the public and the government policymakers (50).

One of the strengths of the present study is the use of a multidimensional model to define vaccine engagement based on a conceptual framework combining perceived vaccine effectiveness and safety with self-declared acceptance and willingness. This combination is assumed to be more reliable than using self-declared acceptance and willingness, as perceived safety and efficacy are less subjected to social desirability bias. Yet, the scale requires further validation to support this assumption. On the other hand, there are no validated instruments to assess attitudes toward the COVID-19 vaccines, and the relevant studies principally used various formulations of self-declared willingness or preparedness, which is limited by the high risk of negative or positive social desirability bias. Future research is recommended in this regard to design a validated scale to measure vaccine acceptance based on a strong model, which will enhance the quality and comparability of the findings. Another strong point of this study is that participants were equally distributed from the 4 regions of the country, which supports the generalizability of the findings. Further, determinants of vaccine acceptance and avoidance were highlighted for the first time nationwide. Therefore, the findings of this study can have a high impact on health authorities' decisions for the management of vaccination campaigns.

The major limitation of this study is the recruitment method of the participants, which was restricted to those who have access to the internet and an electronic device since the questionnaire was shared online. This probably led to a selection bias, occulting a non-negligible section of the population that may have distinct characteristics. One of these characteristics is the source of information regarding COVID-19 disease and vaccine, which may be radically different in the subpopulation of internet non-users by reference to internet users. This may result in discrepant opinions and attitudes toward the vaccine by reference to the study population. Unfortunately, no data was collected about sources of information about the vaccines, which would provide an indication about the aforementioned issue. Nevertheless, a study showed that individuals who get information from the internet are less inclined to accept the COVID-19 vaccine than those who get information from healthcare workers (55). Another aspect of the selection bias is the overrepresentation of medical students and healthcare providers, which was probably due to the snowball sampling method and which limits the generalizability of the findings.

Two-third of Algerians are likely to be non-engaged for COVID-19 vaccine uptake, making them one of the least accepting public for the voluntary vaccination in the MENA region. This probably provides an explanation for the slow ascension of the vaccination curve, which constitutes a great public health concern. These findings and their interpretation should be taken into consideration by the policymakers to acknowledge and address the adverse attitude about the vaccine, notably among healthcare providers who are the vectors and major contributors of a successful vaccine policy. Vaccine awareness campaigns should be implemented to address the multiple misconceptions and enhance the levels of knowledge and perception both about the disease and the vaccine, by prioritizing target populations and engaging both healthcare workers and the general population.

The original contributions presented in the study are included in the article/Supplementary Material, further inquiries can be directed to the corresponding author/s.

SK, SK-D, FY, ME, and MH were responsible for the idea and study design. SK analyzed the data under the supervision of MH. SK, SK-D, FY, and MH wrote the first draft of the manuscript. SG, JS, and MH critically revised the original draft. All authors collected the data, performed systematic review screening and extraction, interpreted the data, shared in the writing, formatting, and approval of the final version.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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