The search results are summarised in Figure 1. In total, 1235 citations were identified, of which 16 were found to be relevant [39,40, 41–48, 49–54] excluded 68 studies.
Quality of the studies
We found 16 observational studies (with 71,465 participants). Of the 16, 15 were quantitative cross-sectional surveys and one qualitative focus group study. All studies recruited participants online. Studies were conducted in 19 countries: three UK, three USA, three China, two Italy, and Canada, Hong Kong, Netherland, Germany, India, Paraguay, Saudi Arabia and Tanzania each with one study. Summary of the studies is in Table 1.
In general, these studies cover one or more of two areas: i) positive impacts (enablers) of SDMs for COVID–19, and ii) specific barriers to control or reduce transmission of COVID–19. Eight important themes under two broad descriptive themes emerged (Fig. 2). The relative contribution of each study to the synthesis is in Table 2.
Table 1 Summary of reviewed studies
Study
|
Aims/study question
|
Country
|
Design/method(s)
|
Number of subjects (sample size)
|
Critical appraisal checklists*
|
Reviewer comments
|
Atchison et al. [39]
|
To examine risk perceptions and behavioural responses of the UK adult population during the early phase of the COVID-19 epidemic.
|
UK
|
Cross-sectional survey
|
2108
|
Quantitative
1,2,4,7,8
|
Lack of methodological details but plausible analysis.
|
Cowling et al. [40]
|
To examine the effect of these interventions and behavioural changes of the public on the incidence of COVID-19, as well as on influenza virus infections, which might share some aspects of transmission dynamics with COVID-19.
|
Hong Kong
|
Cross-sectional telephone survey
|
3013
|
Quantitative
1,2,4,7,8
|
Lack of methodological details but plausible analysis.
|
Gallè et al. [45]
|
To (i) evaluate the level of knowledge about the 2019-nCoV, its spread and the control measures adopted; (ii) analyze health-related behaviours during lockdown, in order to estimate its possible impact on personal habits; (iii) understand if the study field may influence the level of knowledge and lifestyle habits during the pandemic.
|
Italy
|
Quantitative survey
|
2125
|
Quantitative
1,3,7,8
|
Poor methodological details.
|
Hawryluck et al. [47]
|
To assess the level of knowledge about quarantine and infection control measures of persons who were placed in quarantine, to explore ways by
which these persons received information, to evaluate the level of adherence to public health recommendations, and to understand the psychological effect on quarantine.
|
Canada
|
Cross-sectional survey
|
129
|
Quantitative
2,4,7,8
|
Some gaps in methodology.
|
Katz et al. [48]
|
To identify key features of preparedness and the primary concerns of local public health officials in deciding to implement social distancing measures, and determine whether any particular factor could explain the widespread variation among health departments in responses to past outbreaks.
|
USA
|
Online survey
|
150
|
Quantitative
1,2,4,7,8
|
Lack of methodological details but plausible analysis.
|
Pan et al. [50]
|
To evaluate the association of public health interventions with the epidemiological features of the COVID-19 outbreak in Wuhan by 5 periods according to key events and interventions.
|
China
|
Quantitative survey
|
32,583
|
Quantitative
2,4,7,8
|
Some gaps in the methodology.
|
Meier et al. [49]
|
To evaluate public belief in the effectiveness of protective measures, to what extent individuals have implemented these measures in their daily lives, and to identify key communication channels used to acquire information on COVID-19 in
European countries.
|
Netherlands, Germany and Italy
|
Cross-sectional
survey study
|
9796
|
Quantitative
1,2,3,4,7,8
|
Some gaps in methodological details but plausible analysis.
|
Wolf et al. [43]
|
To determine COVID-19 awareness, knowledge, attitudes, and related behaviours among U.S. adults who are more vulnerable to complications of infection because of age and comorbid conditions.
|
USA
|
Cross-sectional survey
|
630
|
Quantitative
1,2,3,4,7,8
|
Few gaps in methodological details but plausible analysis.
|
Roy et al. [52]
|
To assess the knowledge, attitude, anxiety experience, and perceived mental healthcare need among adult Indian population during the COVID-19 pandemic.
|
India
|
Cross-sectional, observational study
|
662
|
Quantitative
1,2,7,8
|
Some gaps in the methodology.
|
Rios-González [51]
|
To examine the knowledge, attitudes and practices of the population about COVID-19.
|
Paraguay
|
Cross-sectional study
|
3141
|
Quantitative
2,3,7,8
|
Some gaps in the methodology.
|
Rugarabamu et al. [41]
|
To investigate KAP towards COVID-19 KAP among residents in Tanzania during the April –May 2020 period of the epidemic.
|
Tanzania
|
Cross-sectional study
|
400
|
Quantitative
2,4,7,8
|
Some gaps in the methodology.
|
Zhong et al. [44]
|
To investigate Chinese residents’ KAP towards COVID-19 during the rapid rise period of the outbreak.
|
China
|
Cross-sectional survey
|
6919
|
Quantitative
1,2,3,4,7,8
|
Some gaps in methodology but overall convincing.
|
Geldsetzer [46]
|
To assess knowledge and perceptions about
COVID-19 among a convenience sample of the general public in the United States and United Kingdom.
|
UK and USA
|
Cross-sectional survey
|
5974
|
Quantitative
2,3,4,7,8
|
Some gaps in methodology but overall convincing.
|
Williams et al. [42]
|
To explore the perceptions and experiences of the UK public of social distancing and social isolation measures related to the COVID-19 pandemic.
|
UK
|
Qualitative – focus group study
|
27
|
Qualitative
1,2,3,4,5,8,9,10
|
Some gaps in methodology but overall convincing.
|
Al-Hanawi et al. [53]
|
To investigate COVID-19 knowledge, attitudes and practices (KAP), and associated sociodemographic characteristics among the general population.
|
Saudi Arabia
|
Cross-sectional study
|
3388
|
Quantitative
1,2,3,4,6,7,8
|
Few gaps in methodological details but plausible analysis.
|
Liu et al. [54]
|
To examine the protective effects of appropriate
personal protective equipment for frontline healthcare professionals who provided care for patients with coronavirus disease 2019 (covid-19).
|
China
|
Cross-sectional study
|
420
|
Quantitative
1,2,3,4,6,7,8
|
Few gaps in methodological details but plausible analysis.
|
*Numbers in this column signify the quality criteria from the critical appraisal checklist (Additional file 3) that studies were deemed to have met.
Table 2 The contribution of each study in a thematic synthesis
|
Atchison et al. [39]
|
Cowling et al. [40]
|
Gallè et al. [45]
|
Hawryluck et al. [47]
|
Katz et al. [48]
|
Pan et al. [50]
|
Meier et al. [49]
|
Wolf et al. [43]
|
Roy et al. [52]
|
Rios-González [51]
|
Rugarabamu et al. [41]
|
Zhong et al. [44]
|
Geldsetzer [46]
|
Williams et al. [42]
|
Al-Hanawi et al. [53]
|
Liu et al. [54]
|
Avoiding crowds and social events
|
|
√
|
√
|
√
|
√
|
√
|
√
|
|
√
|
|
|
√
|
|
√
|
|
|
Reducing reproduction number to avert a local epidemic
|
√
|
√
|
|
|
|
√
|
|
|
|
|
|
|
|
|
|
|
Flatten the peak of and area under the epidemic curve
|
√
|
√
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Improve the capacity and capabilities of the healthcare system
|
√
|
√
|
|
|
√
|
|
|
√
|
|
√
|
|
|
|
|
|
√
|
Appropriate use of physical measures, e.g. hand sanitizers, handwash and face masks
|
|
|
|
|
|
|
√
|
|
|
|
|
|
|
|
|
√
|
Border restrictions, school and border closures to suppress transmission
|
|
√
|
|
√
|
|
|
|
|
|
|
|
|
|
|
|
|
Using multifaceted public health interventions (including border entry restrictions, quarantine and isolation of cases and contacts)
|
√
|
√
|
|
|
|
√
|
√
|
√
|
√
|
√
|
|
|
√
|
|
|
|
Changing population behaviour, such as social distancing and personal protective measures
|
|
√
|
|
|
|
|
|
|
|
|
|
|
|
|
√
|
√
|
Maintain personal hygienic measures
|
|
|
|
|
|
|
√
|
|
√
|
|
|
|
|
|
|
√
|
Compliance with the government actions
|
√
|
√
|
√
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Behavioural changes or interventions which are less disruptive than total lockdown
|
|
|
√
|
|
|
|
|
|
|
|
|
√
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
About the current and second waves or outbreaks
|
|
√
|
|
√
|
|
√
|
√
|
|
|
√
|
|
|
|
√
|
|
|
Uncertainty about the duration of the measures
|
|
|
|
|
|
|
|
|
|
|
|
|
|
√
|
|
|
Lack of trust in governments
|
|
|
|
|
|
|
|
|
|
|
|
|
|
√
|
|
|
Lack of clarity and understanding
|
|
|
|
√
|
|
|
√
|
|
|
√
|
|
|
|
|
|
|
Not receiving the support expected
|
|
|
|
|
|
|
√
|
|
|
√
|
|
|
|
|
|
|
Guidance on social distancing and isolation are vague
|
|
|
|
√
|
|
|
|
|
|
|
|
|
|
|
|
|
Media constantly giving or reporting wrong information about the pandemic status – resulting in emotional exhaustion
|
|
|
√
|
|
|
|
|
|
√
|
|
|
|
|
|
|
|
Worried after seeing posts about COVID-19 pandemic on various social media platforms
|
|
|
|
|
|
|
|
|
√
|
|
|
|
|
|
|
|
Media affecting mental wellbeing and adding to the level of anxiety
|
|
|
|
√
|
|
|
|
|
√
|
|
|
|
|
|
|
|
Fear and anxiety
|
|
|
|
√
|
|
|
|
|
√
|
|
|
|
|
|
|
|
Increased quarantine associated with post-traumatic stress disorder and depression; decrease of physical activity
|
|
|
√
|
√
|
|
|
|
|
|
|
|
|
|
|
|
|
Loss of social interaction and loss of self-worth
|
|
|
|
|
|
|
|
|
√
|
|
|
|
|
√
|
|
|
Lack of social and physical contact.
Lost job or income and relying on parental, familial or state financial support
|
|
|
|
√
|
|
|
|
|
|
|
|
|
|
√
|
√
|
|
COVID-19 associated with ethnic populations in lower socio-economic groups
|
√
|
|
|
√
|
|
√
|
|
√
|
|
|
√
|
|
√
|
√
|
√
|
|
Co-morbidity exposure risks and older age ie over 70
|
√
|
|
|
|
|
|
|
√
|
|
|
√
|
|
|
|
|
|
Note: Shading indicates a study was rated as having low quality in terms of the methodological details
Enablers
Theme 1. Positive impact of social distancing measures
Theme 2. Effective public health interventions
Theme 3. Positive changes in people’s behaviour
Barriers
Theme 4. Worries and concerns about COVID-19
Theme 5. Debatable role of mass media
Theme 6. Physical and psychological impacts
Theme 7. Ethnicity, age and COVID-19 pandemic
Theme 1. Positive impact of social distancing measures
Eleven out of 16 studies identified some positive impacts of different SDMs used to reduce transmission of COVID–19 [39–41,43–46,48,50,51,54]. The commonest SDMs were: avoiding crowds, border restrictions, isolating in the hospital, appropriate use of PPEs, working from home primarily to reduce the effective reproduction number of SARS-CoV–2 (Ro,secondary transmission) [39,40,46,54].
One study has highlighted that:
Without strengthening SDMs, local infections are likely to continue occurring, given that the effective reproduction number (Ro)is approximately 1 or slightly higher. Travel measures and testing, tracing, and treating efforts are particularly important in maintaining suppression, although these measures will be increasingly difficult to implement as case numbers increase [40].
Similarly, other studies further added that if the basic reproduction number of COVID–19 in Hong Kong, UK and US exceeds 2, (it was 2·2 in Wuhan), we would need >44% reduction in COVID–19 transmission to completely avert a local epidemic. A reduction of this magnitude could, however, substantially flatten the peak of and area under the epidemic curve, thus reducing the risk of exceeding the healthcare system capacity, potentially saving many lives, especially older adults [39,40,42,44,51].
Studies reported that quarantine, and school and border closure have been the most effective means of suppressing transmission [40,43]. The commonest factors associated with SDM success are support on governmental measures for social distancing and isolation by avoiding crowds, closure of public places, hand hygiene, and individuals’ adherence to country-specific mitigation measures [45,48].
Theme 2. Effective public health interventions
Ten out of 16 studies reported the importance of public health interventions for COVID–19 [39,40,42,45–49,51,52]. Several studies perceived washing hands with soap, and avoiding crowds and social events as the most effective measures [39,42,45,47,54]. Several studies from different parts of the world reported that multifaceted public health interventions including personal protective equipments (PPEs), e.g. facemasks, eye protection, have been successful as the virus spreads through multiple channels, e.g. touching, sneezing.
The extracts below illustrate this:
The package of public health interventions (including border entry restrictions, quarantine and isolation of cases and contacts, and population behaviour changes, such as social distancing and personal protective measures) that Hong Kong has implemented since late January, 2020, is associated with reduced spread of COVID–19 [40, p. p. e284].
The study participants reported frequent use of sanitizers, hand wash, and masks during the past week. This indicates participants’ increasing concern towards personal hygienic measures. Awareness about COVID–19 is reflected in behaviour and attitude as most participants agreed with social distancing, avoiding travel, self-quarantine and adequate hygiene [48, p.4].
Theme 3: Positive changes in people’s behaviour
We found four studies (of 16) reported SDMs influenced people’s behaviour [39–41, 53]. Atchison et al. [39] reported that part of the success in early February 2020 was changing people’s behaviour to comply with government actions.
The extracts below illustrate this:
Social distancing and population behavioural changes with social and economic impacts less disruptive than total lockdown can meaningfully control COVID–19. Control measures and changes in population behaviour coincided with a substantial reduction in influenza transmission in early February, 2020. This observation suggests the same measures would also have affected COVID–19 transmission in the community, because of some similarities, as well as differences, in the modes of transmission of influenza and COVID–19 [40, p.e285].
Avoiding close contact, washing hands and wearing facial masks were considered the most protective measures [41, p.5].
Barriers
Theme 4: Worries and concerns about COVID–19
Eight out of 16 studies reported some concerns about the current pandemic and a possible second wave of COVID–19 [39,40,42,43,47,49–51]. The commonest associated factors were: (i) uncertainty about the duration of measures, and their ability to cope longer-term [42, p.1], and (ii) lack of trust in public health officials and governments due to lack of clarity about information on infection and what SDMs are effective against COVID–19 [49,51].
The extracts below illustrate this:
Overall, 77.4% (1640/2108) of respondents reported being worried about COVID–19 in the UK. For those not previously testing positive for COVID–19, 47.5% (979/2108) believed it was likely they would be infected at some point in the future under the UK Government’s preventive measures. If infected, just over half (56.9%) would expect to be moderately severely affected (e.g. may need self-care and rest in bed) [39, p.7].
Most participants felt that guidance on social distancing and isolation had been generally unclear, although some described how it had “become clearer”. Many participants exhibited lack of trust in government or in the media [42, p.12].
Theme 5. Debatable role of mass media
Two of 16 studies identified this as a barrier [45,52]. These studies found that rumours in social media, and electronic and print media during SDMs (isolation, self-quarantine), and total restriction of travel (curfew) were associated with negative impact on mental health as they constantly depict the pandemic and deaths related to it. Therefore, people become angry, restless, worried, have difficulty coping, and feel emotionally exhausted [52].
One study observed that:
Approximately 28% of people report sleep difficulties. More than two-thirds of participants reported themselves worried after seeing posts about COVID–19 on social media [52, p.2].
Approximately 46% of participants reported worry regarding discussion of COVID–19 in news channels and print media. This indicates a significant proportion of survey participants, despite having adequate awareness about coronavirus infection, are largely influenced by media information. Media influences mental wellbeing and adds to anxiety levels [52, p.6].
Theme 6: Physical and psychological impacts
Four of the 16 studies identified these barriers [42,45,47,52]. The commonest associated factors were: anxiety [47], increased time in quarantine associated with post-traumatic stress disorder, depression [47], decrease in physical activity [45], loss of social interaction, and emotional and psychological distress [42].
The extracts below illustrate this:
The mandated lack of social and, especially, physical contact with family members were identified as particularly difficult. Confinement at home and work, being unable to see friends, being unable to shop for basic necessities of everyday life, and being unable to purchase thermometers and prescribed medications enhanced their feeling of distance from the outside world [47, p.10].
All participants felt that the social distancing and isolation polices had had significant social and psychological impacts on their lives and the central theme was loss […]. These emotional and psychological losses were particularly acute for those living in more urban, densely populated cities like London or Birmingham. They were also especially evident amongst those in low-paid or precarious occupations, who had either lost their job or income or were now relying on parental, familial or state financial support as a result of the pandemic [42, p.10].
Theme 7: Ethnicity, age and COVID–19 pandemic
We found eight studies that evaluated differences across demographic and socio-economic strata, age and COVID–19 pandemic [39,41–43,46,47,50,53]. These studies found that COVID–19 was often associated with people from Black, Asian and minority ethnic (BAME) populations in lower socio-economic groups, employment in lower band/category, other comorbidities, exposure risks and older age.
The extracts below illustrate this:
More disadvantaged backgrounds were less likely to be able to work from home or self-isolate if needed, suggesting structural barriers to adopting preventive behaviours in these groups. The most economically disadvantaged in society are less able to comply with certain NPIs, likely partly due to their financial situation [39,p.17].
Adoption of SDMs was almost twice as likely in people over 70 compared to adults aged 18 to 34. Notably, those that were single were less likely to practise social distancing. There was a strong association between socio-economic deprivation and ability to adopt NPIs [39,p.15; 43,p.6].
Fig. 3 is a conceptual framework (CF) that emerged from this study, which shows the interconnection of SDMs, factors and reducing COVID–19. To make the effective link between them, all these components are essential; putting people at the centre of the framework, ensuring their needs are appropriately met by providing best-quality care. As the first point of contact for patients or users, primary healthcare would play a key role. The approach would also help to reduce the basic reproduction number (Ro) to avert a local epidemic and flatten the peak of and area under the epidemic curve. Ro is considered a key indicator to assess “whether a pathogen introduced into a community will spread and, significantly gives guidance as to its rate of spread” [53,p.2]. Generally, it is expected to be below 1.0. This CF also acknowledges the capacities and capabilities of primary healthcare systems, health inequalities, social determinants of health, including the capacity of the national laboratory system that appropriately followed the WHO’s mantra of “trace, test, and treat” to suppress and control the coronavirus epidemic [8,11]. Similarly, CF recognises societal norms, culture and values, as each country has its own specific geo-socio-economic, political, legal and cultural contexts.