Knowledge and attitude towards Covid-19 vaccine in Ethiopia: Systematic review and meta-analysis

ABSTRACT

The biggest threat to the effectiveness of vaccination initiatives is a lack of information about and trust in immunization. This study aimed to determine the prevalence of knowledge of and positive attitudes toward the COVID-19 vaccine in Ethiopia. PubMed, Web of Science, Google Scholar, EMBASE, and the Ethiopian University online library were searched. To look for heterogeneity, I² values were computed and an overall estimated analysis was carried out. Although 2108 research articles were retrieved, only 12 studies with a total of 5,472 participants met the inclusion criteria for this systematic review and meta-analysis. The pooled estimates of participants with good knowledge of and positive attitudes toward the COVID-19 vaccine were found to be 65.06% (95% CI: 56.69–73.44%; I² = 82.3%) and 60.15% (95% CI: 45.56–74.74%; I² = 89.4%), respectively, revealing that there is a gap in knowledge of and positive attitudes toward the COVID-19 vaccine in Ethiopia. A holistic and multi-sectoral partnership is necessary for a successful COVID-19 vaccination campaign.

KEYWORDS:

• Knowledge
• attitude
• vaccine
• COVID-19
• COVID-19 vaccine
• Ethiopia

Introduction

Coronavirus disease 2019 (COVID-19) is an emerging respiratory disease caused by a single-strand, positive-sense ribonucleic acid (RNA) SARS-CoV-2 virus (abbreviation for severe acute respiratory syndrome coronavirus type 2).¹ COVID-19 causes morbidity within the range of mild respiratory disease to severe complications characterized by acute respiratory distress syndrome, septic shock, and other metabolic and hemostasis disorders and death.^2,3

Nations have been taking various measures (travel bans and economic lockdowns, declaring states of emergencies to enforce the compulsory wearing of face masks, keeping social/physical distance, prohibition of public gatherings, and closure of faculties) to prevent the fast spread of the virus. However, poor understandings of the diseases among the community and burden of pandemic have made these measures less effective.^4–6

To fight the coronavirus disease (COVID-19) pandemic, researchers from all over the world have made remarkable efforts to create vaccines against the disease.⁷ Vaccination is the most effective ways of controlling infectious disease; reduce the occurrence of severe disease and death.⁸ However, individuals and groups who choose to delay or refuse to take vaccines challenge the success of vaccine program.⁹ Vaccine hesitancy is believed to be responsible for decreasing vaccine coverage, increased risk of vaccine preventable disease outbreaks and caused by multiple factors, mainly; due to poor knowledge and unfavorable attitude toward the vaccine.^10–13

Knowledge and attitude toward COVID-19 vaccine is affected by lack of information or the spread of misinformation (define as incorrect or erroneous information conveyed regardless of intent to deceive) by many platforms (media, news headlines, talk programs, and popular publications) and lack of trust in immunization.^14–19 These factors have the potential to have serious negative repercussions, as individuals become not only uninformed but also less able to believe in scientific truths and trust experts.^15–18 Many people in developing nations still believe that vaccination is dangerous and unneeded,²⁰ which leads to vaccine hesitation and anti-vaccination behavior in the community.^{18–19,21–24} Therefore, studying knowledge and attitude toward COVID-19 vaccine among the general population is an interesting topic to reduce COVID-19 diseases transmission rate in Ethiopia.²⁵

Based on studies conducted in different region of Ethiopia, the prevalence of good knowledge about the COVID-19 vaccine among general population was between 46.8%−79.2%^25–31 and favorable attitude toward COVID-19 vaccine was between 24.2%−95.6%.^25–36 Given these variations, there is no overall estimate of the prevalence of knowledge and attitude toward COVID-19 vaccine at national level. Therefore, this study aimed to determine the pooled prevalence of knowledge and attitude regarding of COVID-19 vaccine among the general population in Ethiopia. The study will provide fundamental data for policymakers, clinicians, and other stakeholders in order to help develop an appropriate strategies and interventions for COVID-19 vaccine campaign in Ethiopia.

Methods

Eligibility criteria

All studies reported the prevalence of knowledge, attitude, or both of COVID-19 vaccine, used English language for reporting, had full text available for search, done by cross-sectional study design and conducted only in Ethiopia were included in this systematic review and meta-analysis. Studies reported duplicated sources, unrelated research topic, used design other than cross-sectional study, and articles with no full text available (insufficient data and outcome of interest not reported) and attempts to contact the corresponding author via e-mail not possible were excluded this systematic review and meta-analysis.

Search strategy

Both manual search (google and google scholar) and electronic search with indexed database search (PubMed, Web of Science, and EMBASE) were used to identify relevant articles. Various other gray literature databases (searching from the reference lists of the included studies, websites of government agencies and the Ethiopian institutional research repositories) were used. We applied search terms independently and/or in combination using “OR,” “AND” or “NOT.” In EMBASE, we used Boolean operators and Emtree terms (a controlled vocabulary or standard words used to make searching easier) to identify relevant articles, whereas in Web of science we used synonyms, Boolean operators, key words, and topics. In Google Scholar and other manual search, key words/phrases were used. In PubMed medical subject headings (MeSH) terms was used as follows: (((((((((((((COVID-19) OR (SARS-2)) OR (coronavirus)) OR (highly contagious diseases)) AND (vaccine)) OR (immunization)) OR (preventive measures)) OR (COVID-19 vaccine)) OR (SARS-2 vaccine)) OR (coronavirus vaccine)) AND (knowledge)) OR (awareness)) AND (attitude)) AND (Ethiopia).

The review was commenced from Oct 15, 2022 to Nov 15, 2022. All of the accessible studies that had been published in English up to Nov 15, 2022 were included in the present meta-analysis and systematic review.

In terms of reporting the findings of the literature search, the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guideline was used³⁷ (S1 File). The systematic review was prospectively registered on International Prospective Register of Systematic Reviews (PROSPERO) with unique of number CRD42022373035.

Study selection and data extraction

After imported the articles from the databases to Endnote reference manager version 7, duplicates of articles were checked and removed systematically. Three independent authors (GA, AY, and NA) have screened and reviewed the title and abstract. Any disagreement was resolved through discussions lead by a fourth author (EC). Additionally, these authors have reviewed the full text and extracted the relevant data from the articles, which fulfilled the inclusion criteria.

The name of the first author, year of publication, study region, study setting, study population, the prevalence of knowledge of COVID-19 vaccine, the prevalence of attitudes toward COVID-19 vaccine, sample size, number of cases of knowledge about COVID-19 vaccine, number of cases of attitude toward COVID-19 vaccine were extracted carefully on an Excel spreadsheet.

Quality assessment

The two independent authors (GA and NA) appraised the quality of the included studies^25–36 using the Joanna Briggs Institute (JBI) quality appraisal checklist for cross-sectional studies.³⁸ Any disagreement was discussed and resolved by the third author (MM). The critical analysis checklist has eight parameters with yes, no, unclear, and not an applicable options. Studies were considered low risk when they scored 50% and above of the quality assessment indicators as reported in supplementary file (S2 File).

Risk of bias assessment

This systematic review and meta-analysis study used a risk of bias assessment tool developed by Hoy et al³⁹ consisting of 10 items that assess four domains of bias, internal and external validity. The risk of bias was assessed by three independent authors (DN, MA, KD) for included studies.^25–36 The first four items (items1–4) evaluate the presence of selection bias, non-response bias and external validity. The other six items (items 5–10) assess the presence measurement bias, analysis-related bias, and internal validity. Therefore, studies that received ‘yes’ for eight or more of the 10 questions were classified as ‘low risk of bias.’ Studies that received ‘yes’ for six to seven of the 10 questions were classified as ‘moderate risk’, whereas studies that received ‘yes’ for five or fewer of the 10 questions were classified as ‘high risk’ as reported in (S3 File).

Outcome measurement

Knowledge about COVID-19 vaccine

Study participants who responded ≥50% of knowledge-related questions were thought to have good knowledge about COVID-19 vaccine, whereas study participants who responded ≤50% of knowledge-related questions were considered to have poor knowledge about COVID-19 vaccine.

Attitude toward the COVID-19 vaccines

Accordingly, study participants who responded ≥50% of attitude-related questions were considered to have positive attitude toward COVID-19 vaccine, whereas study participants who responded ≤50% of attitude-related questions were considered to have negative attitude toward COVID-19 vaccine

Statistical analysis

Firstly, selected articles were entered into Microsoft Excel spreadsheet format and imported to STATA version 14. statistical software for analysis. Weighted inverse variance random effect model was used to estimate the pooled prevalence of knowledge about COVID-19 vaccine and attitude toward COVID-19 vaccine among the general population in Ethiopia. We used random effect model because there is heterogeneity between studies. Cochrane Q-test and I² statistics were computed to assess heterogeneity among all studies. Accordingly, values of I² 0, 25, 50, and 75% represented no, low, medium, and high heterogeneity, respectively.

Funnel plot, Begg and Egger’s regression tests were done to assess publication bias. The p value > .05 indicated that there was no publication bias. A trim and fill analysis was done to see the effect of publication bias.

Subgroup analysis was done based on the study region, study population and year of publication. Forest plot format was used to present the pooled prevalence knowledge about COVID-19 vaccine and attitude toward COVID-19 vaccine with 95%CI.

Results

Search results

There were 2108 articles found in the databases including, 693 from PubMed, 1215 from Google Scholar, 52 from EMBASES, 121 from Web of sciences, 6 from Ethiopian universities’ research repositories, and 21 from the reference lists of included studies. While a total of 2096 articles were excluded due to various reasons. For instance, 456 articles were removed because of duplicates, 1603 due to irrelevant titles and abstracts, 16 due to the study designs, 9 due to study areas, 9 insufficient data and 3 outcome of interest not reported. Finally, 12^25–36 articles were included in the study. From the included studies, seven articles, 11 articles, and 6 articles reported prevalence of knowledge, attitude, and both knowledge and attitude about COVID-19 vaccine (Figure 1).

Figure 1. PRISMA flow diagram of articles screened and the selection process on prevalence of knowledge and attitude towards COVID-19 vaccine in Ethiopia.

Characteristics of included studies

In this study, a total of 12 articles^25–36 with a sample size of 5,472 study participants were included in the analysis. The author’s names, publication year, study design, sample size, study setting, the prevalence of knowledge and attitude toward COVID-19 vaccine, number of cases of knowledge and attitude toward COVID-19 vaccine were listed.

The majority of the studies (4 articles)^25–28 were conducted in the South Nation Nationalities and Peoples’ region (SNNP), three from Amhara,^29,31,33 one from Oromia,³⁶ one from Adis Ababa³⁰ and the remaining three studies were conducted through an online survey by sending the questionnaire through e-mail, telegram, and other means of communication for those who able to access the internet.^32,34,35 Regarding publication year, the earliest in 2021 and the latest in Sep 29, 2022. The sample sizes ranged from 319 to 668. The prevalence of knowledge and attitude toward COVID-19 vaccine were ranged from 46.8% to 79.2% and 24.2 to 95.6%, respectively. From the included studies, seven articles, 11 articles, and 6 articles reported prevalence of knowledge, attitude, and both knowledge and attitude about COVID-19 vaccine. All 12 studies were assessed using the Joanna Briggs Institute (JBI) quality appraisal checklist. Two of the included studies had reported moderate risk^31,34 and the rest had reported low risk. A detailed description of the studies was found in Table 1.

Table 1. Descriptions of the studies used in the systematic review and meta-analysis for the knowledge and attitude toward COVID-19 vaccine in Ethiopia.

Serial number	Authors	Year	Region	Study area	Study population	sample size	Prevalence of good Knowledge	Prevalence of positive attitude	Number of study participant with good knowledge	Number of study participant with positive attitude	Study quality
1	Abebe H, Shitu S, Mose A	2021	SNNP	Gurage zone	Adult population	492	74.0%	44.7%	364	220	Low risk
2	Adane M, Ademas A, Kloos H	2022	Amhara region	Dessie city	HCW	392	62.5%	52.3%	245	205	Low risk
3	Mesesle M	2021	National	National	General population	425	Not reported	24.2%	Not reported	103	Low risk
4	Alle YF, Oumer KE	2021	Amhara region	Debre Tabor hospital	HCW	319	Not reported	42.3%	Not reported	135	Low risk
5	Adella GA et al.	2022	SNNP	Woliata zone	Patients with chronic disease	409	79.2%	70.9%	324	290	Low risk
6	Ahmed MH et al.	2021	SNNP	Selected hospitals in southern region	HCW	409	64.0%	95.6%	262	391	Low risk
7	Guangul BA et al.	2021	National	National	HCW	668	Not reported	64.0%	Not reported	428	Moderate risk
8	Tadele Admasu.	2021	Adis Ababa	Adis Ababa	Cancer patients	422	68.0%	Not reported	287	Not reported	Low risk
9	Abay ES et al.	2022	National	National	Clinical practitioner	461	Not reported	86.1%	Not reported	397	Low risk
10	Asmare Adella G.	2022	SNNP	Southern Public universities	University teachers	418	60.8%	79.7%	254	333	Low risk
11	Tolossa T et.al.	2022	Oromia region	Nekemte	HCW	431	Not reported	51.3%	Not reported	221	Low risk
12	Aklil MB, Temesgan WZ	2022	Amhara region	Gondar city	College students	626	46.8%	50.0%	293	313	Moderate risk

NB; SNNP- South Nation Nationalities and Peoples, HCW-Health Care Workers.

Level of knowledge and attitude toward COVID-19 vaccine

The pooled prevalence of the knowledge about and attitudes toward COVID-19 vaccine among the general population in Ethiopia is presented by the forest plots in Figures 2 & 3. A random-effect model showed that the pooled level of good knowledge about COVID-19 vaccine was 65.1% (95% CI: 56.7–73.4%; I² = 82.3%). The overall pooled estimated positive attitude toward COVID-19 vaccine was 60.2% (95% CI: 45.6–74.7%; I² = 89.4%) (Figures 2 and 3).

Figure 2. Forest plot of knowledge with the height of the diamond is the overall effect size (ES) (65.1%) while the width is the confidence interval (CI) at 95% (56.7–73.4%). The y-axis shows the standard error of each study while the x-axis the estimate of effect size of the each study. The vertical dotted line denotes the no effect. The box represents the effect size of each study and the line across the box is confidence interval of each study.

Figure 3. Forest plot of attitude with the height of the diamond is the overall effect size (ES) (60.2%) while the width is the confidence interval (CI) at 95% (45.6–74.7%). The y-axis shows the standard error of each study while the x-axis the estimate of effect size of the each study. The vertical dotted line denotes the no effect. The box represents the effect size of each study and the line across the box is confidence interval of each study.

Leave – one- out sensitivity analysis

A leave-one-out sensitivity analysis was conducted to show the influence of each study on the pooled prevalence of a good level of knowledge about and a positive attitude toward COVID-19 vaccine by excluding one study at a time.

Based on the finding from sensitivity analysis, two studies in the review had an impact on the pooled level of good knowledge about COVID-19 vaccine^28,31 and attitude toward COVID-19 vaccine^26,32 (Table 2).

Table 2. A leave – out-one sensitivity analysis for knowledge and attitude toward COVID-19 vaccine in Ethiopia.

Study omitted	Pooled estimate	95% Confidence interval (CI)
Knowledge related article
Abebe H, Shitu S, Mose A/2021	63.6%	54.2%-72.9%
Adane M, Ademas A, Kloos H/2022	65.5%	55.8%-75.2%
Adella GA et.al./2022	62.7%	54.6%-70.7%
Ahmed MH et.al./2021	65.2%	55.5%-75.0%
Tadele Admasu/2021	64.6%	54.8%-74.4%
Asmare Adella G/2022	65.8%	56.1%-75.4%
Aklil MB, Temesgan WZ/2022	68.2%	62.2%-74.1%
Attitude related article
Abebe H, Shitu S, Mose A/2021	61.7%	46.4%- 76.9%
Adane M, Ademas A, Kloos H/2022	60.9%	45.4%- 76.5%
Mesesle M/2021	63.8%	50.5%-77.0%
Alle YF, Oumer KE/2021	61.9%	46.7%-77.1%
Adella GA et al./2022	59.1%	43.1%-75.0%
Ahmed MH et al./2021	56.6%	44.1%-69.1%
Guangul BA et al./2021	59.8%	43.6%-75.9%
Abay ES et al./2022	57.5%	41.5%-73.5%
Asmare Adella G/2022	58.2%	42.2%-74.2%
Tolossa T et al./2022	61.0%	45.5%-76.6%
Aklil MB, Temesgan WZ/2022	61.2%	45.6%-76.7%

Subgroup analysis

In this subgroup analysis, the level of good knowledge and positive attitude toward COVID-19 were examined by study region, study population, and year of publication. The subgroup analysis based on region showed that a level of good knowledge were 69.6% in SNNP region, 54.6% in Amhara region and 68.0% in Adis Ababa. Based on study population, 74.0% in adult population (age>18), 63.3% in healthcare workers and 46.8% in college students. Based on year of publication, 68.8% of a good level of knowledge was in 2021 and 62.3% in 2022.

With regard to positive attitude toward COVID-19 vaccine, the subgroup analysis based on region showed that 72.8% in SNNP region, 48.4% in Amhara region, 58.2% at national level and 51.3% in Oromia region. Based on study population, 44.7% in adult population (age > 18), 65.4% in health-care workers and 50.0% in college students. Based on year of publication, 54.2% of a positive attitude was in 2021 and 65.1% in 2022 (Table 3).

Table 3. The overall estimated level of good knowledge and positive attitude toward COVID-19 vaccine in Ethiopia, 95% CI and heterogeneity estimate with a p-value for sub-group analysis.

Variable	Characteristics	Pooled level of good knowledge at 95% (CI)	I^2 (p-value)
Knowledge related articles
Region	SNNP region	69.6% (61.3–77.9%)	83.5% (.000)
	Amhara region	54.6%(39.2–69.9%)	86.0%(.000)
	Adis Ababa	68.0% (63.6–72.5%)	0%(.000)
Study population	All adult population	74.0% (70.1–77.9%)	0%(.000)
	Health care workers (HCW)	63.3% (60.0–66.6%)	72.2% (.000)
	Patients with chronic diseases	79.2% (75.3–83.2%)	0%(.000)
	Cancer patients	68.0% (63.6–72.5%)	0%(.000)
	University teachers	60.8% (56.1–65.5%)	0%(.000)
	College students	46.8%(42.9–50.7%)	0%(.000)
Year of publication	2021	68.8% (63.0–74.6%)	81.5%(.004)
	2022	62.3%(48.1–76.6%)	89.7% (.000)
Attitude related articles
Region	SNNP region	72.8% (50.9–94.7%)	92.4% (.000)
	Amhara region	48.4% (43.0–53.8%)	74.3% (.021)
	National	58.2% (23.5–89.8%)	96.3% (.000)
	Oromia region	51.3% (46.6–56.0%)	0%(.000)
Study population	All adult population	44.7% (40.5–49.1%)	0%(.000)
	Health care workers (HCW)	65.4% (47.3–83.5%)	97.4% (.000)
	All population	24.2% (20.2–28.3%)	0%(.000)
	Patients with chronic diseases	70.9% (66.5–75.3%)	0%(.000)
	University teachers	79.7% (75.8–83.5%)	0%(.000)
	College students	50.0% (46.1–53.9%)	0%(.000)
Year of publication	2021	54.2% (24.8–83.7%)	97.9% (.000)
	2022	65.1% (51.6–78.6%)	96.5% (.000)

NB; SNNP- South Nation Nationalities and Peoples, CI-Confidence Interval.

Publication bias

The presence of publication bias was checked using funnel plot visualization and Egger’s and Begg’s regression tests (P < .05). The funnel plot visualization was symmetric distribution for good level of knowledge about COVID-19 vaccine. The Egger and Begg tests both revealed no statistical evidence of publication bias for a good level of knowledge (P = .9 and P = .4, respectively).

The funnel plot visualization was asymmetric distribution for positive level of attitude toward COVID-19 vaccine, but the results of the Begg (P = .1) and Egger (P = .1) tests showed the absence of publication bias (Figure 4).

Figure 4. For the top figure funnel plot showing symmetrical distribution of studies indicating the visual absence of publication bias for included studies reporting knowledge. For the bottom figure funnel plot showing asymmetrical distribution of studies indicating the visual presence of publication bias for included studies reporting attitude. For both the top and bottom figures, the Y-axis is the standard error and the X-axis is the study result or effect size. The dotted diagonal line of the funnel is the 95% confidence interval and the vertical. The vertical dotted line is the line of no-effect and dots are included studies reporting knowledge of and attitude towards COVID-19 vaccine.

Discussion

Due to the scant availability of literature, we conducted this systematic review and meta-analysis to better understand attitudes and levels of knowledge regarding the COVID-19 vaccine among the general population in Ethiopia. We included all eligible studies^25–36 found via a variety of electronic search engines and undertook a subgroup analysis to assess the proportion of people with good knowledge and positive attitudes by study region, study population and year of publication.

This study’s findings revealed that the pooled prevalence of good knowledge about the COVID-19 vaccine was 65.1% (95% CI: 56.7–73.4%), which was consistent with a study conducted in Bangladesh (62.1%)⁴⁰ and higher than in West India (35.5%) and Malaysia (38.0%).^41,42 However, levels of good knowledge were higher than our finding in Greece (88.3%), Oman (88.4%) and Romania (95.2%).^43–45 This could be attributed to variations in the spread and burden of COVID-19 across these countries.⁴⁶ The discrepancy could also be due to differences in the respondents’ local norms and cultures and exposure to credible social media disseminating information regarding the vaccine.^47,48 The variation could also be explained by differences in awareness of the severity of COVID-19 and access to healthcare services. The pooled prevalence showed that significant numbers of Ethiopians (about 35.0% of the study population) had poor knowledge of the COVID-19 vaccine. This implies that improving knowledge regarding the benefits, effectiveness, and safety of the COVID-19 vaccine could be a strategy for achieving vaccination coverage goals in the general population. Having good knowledge is a driver for receiving the COVID-19 vaccine, as it helps individuals understand the seriousness of the disease and the benefits of vaccination.

This study’s findings revealed that the pooled prevalence of positive attitudes toward the COVID-19 vaccine was 60.2% (95% CI: 45.6–74.7%), which was consistent with studies done in Belgium (72.4%) and Italy (50.0%)^49,50 and higher than in studies examining the UK (36.9%) and Egypt (34.3%).^51,52 This variation may be explained by differences in culture, socio-economic status, and health policy implementation.

The results of the subgroup analysis indicated that the pooled proportion of positive attitudes toward the COVID-19 vaccine among healthcare workers in Ethiopia was 65.4%. This implies that a considerable proportion of healthcare workers hold unfavorable views, making them less likely to recommend vaccination to their patients. Evidence indicates that healthcare workers’ attitudes toward the COVID-19 vaccine were found to influence their intention to suggest the vaccine to their patients and the general population.⁵³ Hence, future educational priorities need to focus on healthcare workers to influence their own use of the vaccine and help the general population accept vaccination.

In this study, we used a random-effect model to manage a significant variation that resulted in between-study heterogeneity. We assessed leave-one-out sensitivity and the results show that every study had a significant impact on the pooled good level of knowledge and positive attitudes. We also assessed possible variability sources via subgroup analysis using the study populations and regions and years of publication. The high degree of heterogeneity may be due to differences in the sample populations, paper quality, or socio-cultural, ethnic, and regional differences.

Strengths and limitations of the study

The strengths of the study include the use of a comprehensive electronic search strategy through a variety of datasets to determine overall levels of knowledge and attitudes toward the COVID-19 vaccine, the use of JBI-MAStARI appraisal, and access to gray literature. The limitations included the absence of standard measurement of ‘good knowledge’ and ‘positive attitude’ among different groups of the population that the research team could operationalize, and the research may be biased. The absence of a similar previous study makes it very difficult to compare the findings of this study. Predictors of knowledge and attitudes toward the COVID-19 vaccine were missed. Hence, future researchers should consider the factors related to knowledge and attitudes regarding the COVID-19 vaccine. Since some regions did not report knowledge or attitude data, the results of this study were not representative of all regions in Ethiopia.

Conclusion

In conclusion, this systematic review and meta-analysis reported that there was a significant gap in good knowledge of and positive attitudes toward the COVID-19 vaccine in Ethiopia. In addition, the pooled prevalence of good knowledge and positive attitudes differed based on study populations, regions and years of publication. A holistic and multi-sectoral partnership is necessary for a successful COVID-19 vaccination campaign. Further health education and communication are crucial methods for improving knowledge and attitudes regarding the COVID-19 vaccine, and finally, to improve vaccine acceptance.

Authors’ contribution

All authors made considerable contributions to conception and design, acquisition of data, or evaluation and interpretation of data; took section in drafting the article or revising it significantly for necessary intellectual content; agreed to put up to the current journal; gave ultimate approval of the version to be published; and agree to be responsible for all elements of the work.

Availability of data and material

All data generated or analyzed during study are included in this systematic review and meta-analysis.

Ethics approval and consent to participate

Ethics approval and consent to participate are not applicable since we used already previously done research.

Acknowledgments

Our special gratitude goes to the authors of included studies who helped us to do this systematic review and meta-analysis.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed on the publisher’s website at https://doi.org/10.1080/21645515.2023.2179224

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.