Comparative effectiveness of contact tracing interventions in the context of the COVID-19 pandemic: a systematic review.

Contact tracing is a non-pharmaceutical intervention (NPI) widely used in the control of the COVID-19 pandemic. Its effectiveness may depend on a number of factors including the proportion of contacts traced, delays in tracing, the mode of contact tracing (e.g. forward, backward or bidirectional contact training), the types of contacts who are traced (e.g. contacts of index cases or contacts of contacts of index cases), or the setting where contacts are traced (e.g. the household or the workplace). We performed a systematic review of the evidence regarding the comparative effectiveness of contact tracing interventions. 78 studies were included in the review, 12 observational (ten ecological studies, one retrospective cohort study and one pre-post study with two patient cohorts) and 66 mathematical modelling studies. Based on the results from six of the 12 observational studies, contact tracing can be effective at controlling COVID-19. Two high quality ecological studies showed the incremental effectiveness of adding digital contact tracing to manual contact tracing. One ecological study of intermediate quality showed that increases in contact tracing were associated with a drop in COVID-19 mortality, and a pre-post study of acceptable quality showed that prompt contact tracing of contacts of COVID-19 case clusters / symptomatic individuals led to a reduction in the reproduction number R. Within the seven observational studies exploring the effectiveness of contact tracing in the context of the implementation of other non-pharmaceutical interventions, contact tracing was found to have an effect on COVID-19 epidemic control in two studies and not in the remaining five studies. However, a limitation in many of these studies is the lack of description of the extent of implementation of contact tracing interventions. Based on the results from the mathematical modelling studies, we identified the following highly effective policies: (1) manual contact tracing with high tracing coverage and either medium-term immunity, highly efficacious isolation/quarantine and/ or physical distancing (2) hybrid manual and digital contact tracing with high app adoption with highly effective isolation/ quarantine and social distancing, (3) secondary contact tracing, (4) eliminating contact tracing delays, (5) bidirectional contact tracing, (6) contact tracing with high coverage in reopening educational institutions. We also highlighted the role of social distancing to enhance the effectiveness of some of these interventions in the context of 2020 lockdown reopening. While limited, the evidence from observational studies shows a role for manual and digital contact tracing in controlling the COVID-19 epidemic. More empirical studies accounting for the extent of contact tracing implementation are required.

Communicating risk during early phases of COVID-19: Comparing governing structures for emergency risk communication across four contexts.

Background: Emergency risk communication (ERC) is key to achieving compliance with public health measures during pandemics. Yet, the factors that facilitated ERC during COVID-19 have not been analyzed. We compare ERC in the early stages of the pandemic across four socio-economic settings to identify how risk communication can be improved in public health emergencies (PHE). Methods: To map and assess the content, process, actors, and context of ERC in Germany, Guinea, Nigeria, and Singapore, we performed a qualitative document review, and thematically analyzed semi-structured key informant interviews with 155 stakeholders involved in ERC at national and sub-national levels. We applied Walt and Gilson's health policy triangle as a framework to structure the results. Results: We identified distinct ERC strategies in each of the four countries. Various actors, including governmental leads, experts, and organizations with close contact to the public, collaborated closely to implement ERC strategies. Early integration of ERC into preparedness and response plans, lessons from previous experiences, existing structures and networks, and clear leadership were identified as crucial for ensuring message clarity, consistency, relevance, and an efficient use of resources. Areas of improvement primarily included two-way communication, community engagement, and monitoring and evaluation. Countries with recurrent experiences of pandemics appeared to be more prepared and equipped to implement ERC strategies. Conclusion: We found that considerable potential exists for countries to improve communication during public health emergencies, particularly in the areas of bilateral communication and community engagement as well as monitoring and evaluation. Building adaptive structures and maintaining long-term relationships with at-risk communities reportedly facilitated suitable communication. The findings suggest considerable potential and transferable learning opportunities exist between countries in the global north and countries in the global south with experience of managing outbreaks.

A comparative analysis of experienced uncertainties in relation to risk communication during COVID19: a four-country study.

BACKGROUND: During outbreaks, uncertainties experienced by affected communities can influence their compliance to government guidance on public health. Communicators and authorities are, hence, encouraged to acknowledge and address such uncertainties. However, in the midst of public health crises, it can become difficult to define and identify uncertainties that are most relevant to address. We analyzed data on COVID-19-related uncertainties from four socio-economic contexts to explore how uncertainties can influence people's perception of, and response to Risk Communication and Community Engagement (RCCE) strategies. RESULTS: This qualitative study, which adopts an interpretative approach, is based on data from a documentary review, key informant interviews (KII), and focus group discussions (FGD) with members of the general public and people with barriers to information from Germany, Guinea, Nigeria, and Singapore. Transcripts from the KII and FGD were coded and analyzed thematically. We interviewed a total of 155 KIs and conducted 73 FGD. Our analysis uncovered a divergence between uncertainties deemed relevant by stakeholders involved in policy making and uncertainties that people reportedly had to navigate in their everyday lives and which they considered relevant during the pandemic. We identified four types of uncertainties that seemed to have influenced people's assessment of the disease risk and their trust in the pandemic control strategies including RCCE efforts: epidemiological uncertainties (related to the nature and severity of the virus), information uncertainties (related to access to reliable information), social uncertainties (related to social behavior in times of heightened risk), and economic uncertainties (related to financial insecurities). CONCLUSION: We suggest that in future outbreaks, communicators and policy makers could improve the way in which affected communities assess their risk, and increase the trust of these communities in response efforts by addressing non-epidemiological uncertainties in RCCE strategies.

Systematic review of empirical studies comparing the effectiveness of non-pharmaceutical interventions against COVID-19.

OBJECTIVES: To evaluate which non-pharmaceutical interventions (NPIs) have been more and less effective in controlling the COVID-19 pandemic. METHODS: We performed a systematic review of published and unpublished empirical studies, either observational or interventional, analysing the comparative effectiveness of NPIs against the COVID-19 pandemic. We searched Embase/Medline and medRxiv to identify the relevant literature. RESULTS: We identified 34 studies. During the first wave of the COVID-19 pandemic, school closing was the most effective NPI, followed by workplace closing, business and venue closing and public event bans. Public information campaigns and mask wearing requirements were also effective in controlling the pandemic while being less disruptive for the population than other NPIs. There was no evidence on the effectiveness of public transport closure, testing and contact tracing strategies and quarantining or isolation of individuals. Early implementation was associated with a higher effectiveness in reducing COVID-19 cases and deaths, while general stringency of the NPIs was not. CONCLUSIONS: In this systematic review, we found that school closing, followed by workplace closing, business and venue closing and public event bans were the most effective NPIs in controlling the spread of COVID-19. An early response and a combination of specific social distancing measures are effective at reducing COVID-19 cases and deaths. Continuous monitoring of NPIs effectiveness is needed in order to adapt decision making.

The impact of non-pharmaceutical interventions on COVID-19 epidemic growth in the 37 OECD member states.

We estimated the impact of a comprehensive set of non-pharmeceutical interventions on the COVID-19 epidemic growth rate across the 37 member states of the Organisation for Economic Co-operation and Development during the early phase of the COVID-19 pandemic and between October and December 2020. For this task, we conducted a data-driven, longitudinal analysis using a multilevel modelling approach with both maximum likelihood and Bayesian estimation. We found that during the early phase of the epidemic: implementing restrictions on gatherings of more than 100 people, between 11 and 100 people, and 10 people or less was associated with a respective average reduction of 2.58%, 2.78% and 2.81% in the daily growth rate in weekly confirmed cases; requiring closing for some sectors or for all but essential workplaces with an average reduction of 1.51% and 1.78%; requiring closing of some school levels or all school levels with an average reduction of 1.12% or 1.65%; recommending mask wearing with an average reduction of 0.45%, requiring mask wearing country-wide in specific public spaces or in specific geographical areas within the country with an average reduction of 0.44%, requiring mask-wearing country-wide in all public places or all public places where social distancing is not possible with an average reduction of 0.96%; and number of tests per thousand population with an average reduction of 0.02% per unit increase. Between October and December 2020 work closing requirements and testing policy were significant predictors of the epidemic growth rate. These findings provide evidence to support policy decision-making regarding which NPIs to implement to control the spread of the COVID-19 pandemic.

Assessing COVID-19 through the lens of health systems' preparedness: time for a change.

The last months have left no-one in doubt that the COVID-19 pandemic is exerting enormous pressure on health systems around the world, bringing to light the sub-optimal resilience of even those classified as high-performing. This makes us re-think the extent to which we are using the appropriate metrics in evaluating health systems which, in the case of this pandemic, might have masked how unprepared some countries were. It also makes us reflect on the strength of our solidarity as a global community, as we observe that global health protection remains, as this pandemic shows, focused on protecting high income countries from public health threats originating in low and middle income countries. To change this course, and in times like this, all nations should come together under one umbrella to respond to the pandemic by sharing intellectual, human, and material resources. In order to work towards stronger and better prepared health systems, improved and resilience-relevant metrics are needed. Further, a new model of development assistance for health, one that is focused on stronger and more resilient health systems, should be the world's top priority.