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Table 1 Study characteristics

From: Lessons from past pandemics: a systematic review of evidence-based, cost-effective interventions to suppress COVID-19

Last name of the first author Year of publication Study design Intervention(s) Key finding(s)
Ahmed 2018 Review Workplace social distancing Modelling studies estimated workplace social distancing reduced the cumulative influenza attack rate 23%.
Armbruster 2007 Modelling Contact tracing
Screening
Contact tracing is cost-effective only when population prevalence is low (e.g. under 8% for tuberculosis)
Barnes 2007 Modelling Case isolation
Personal protection equipment
Antiviral prophylaxis
Antiviral prophylaxis can contain an influenza strain with R0 = 2; healthcare workers contribute disproportionately to the transmission of the infection when not protected against infection.
Becker 2005 Modelling Face masks
Social distancing
Hand hygiene
Case isolation
School closures
Quarantining affected households
Contact tracing
Combinations more effective than single interventions; household quarantines and contact tracing reduced reproduction number from 6 to below 1.
Bell 2006 Review Travel restrictions Screening and quarantining entering travellers were ineffective in past pandemics; WHO recommends providing information to international travellers and screening travellers departing infected countries.
Bell 2006 Review School closures
Isolation of patients
Quarantine of contacts
Antiviral therapy
Travel restrictions
Hand hygiene
Respiratory hygiene
Face masks
Disinfected household surfaces
At the start of the outbreak, detect and isolate cases, quarantine contacts, restrict travel in and out of affected communities, and consider targeted antiviral therapy. If sustained transmission in the general population, ill persons are advised to remain at home; increase social distance; promote hand-washing and respiratory hygiene/cough etiquette; wear face masks; and disinfect contaminated household surfaces.
Bin Nafisah 2018 Review School closures School closures reduced the peak of epidemics by an average of 29.65%.
Bolton 2012 Modelling School closures
Travel restrictions
Generalized social distancing
Quarantining of close contacts
Treatment of cases with antivirals
Prophylaxis of contacts
A combination of non-pharmaceutical interventions proved as effective as the targeted use of antivirals and reduced the mean attack rate from approximately 23 to 21% (severe pandemic scenario).
Bootsma 2007 Observational School closures
Church closures
Mass gatherings
Face masks
Case isolation
Disinfection/hygiene measures
The timing of interventions during the 1918–1919 flu pandemic (specifically early intervention) was the most strongly correlated factor with total mortality. Population size and density were not significant factors in overall mortality.
Buonomo 2012 Modelling Health promotion campaign
Vaccination
Early vaccination is more cost-effective; interventions before vaccines are available need to be balanced with the potential gains in the cost-effectiveness of future vaccines.
Caley 2007 Modelling Border screening
Face masks during transit
Immediate presentation following symptom onset
Flight-based quarantining
The most effective strategy to prevent spread is control in the source country; targeting travellers is not effective.
Chen 2020 Modelling School closure
Case isolation
Antiviral treatment
Antiviral prophylaxis
Vaccination
Case isolation was the most effective single intervention, adding antiviral therapeutics, antiviral prophylaxis, vaccination prior to the outbreak, and school closure decreased the attack rate only slightly and shortened outbreak duration by only 9 days
Chinazzi 2020 Modelling Travel restrictions 90% travel restrictions to and from China only modestly affect the epidemic trajectory unless combined with a 50% or higher reduction of transmission in the community.
Chong 2012 Modelling Travel restrictions (air, land, sea)
Antiviral treatment
Restricting air travel from infected regions 99% delays epidemic peak up to 2 weeks. Restricting air and land travel delays peak ~3.5 weeks. Neither 90% nor 99% travel restrictions reduced the epidemic magnitude more than 10%. Antiviral treatment and hospitalization of infectious subjects are more effective.
Dan 2009 Modelling Personal protection equipment
Personal protection equipment plus restricting visitors and cancelling elective procedures
Personal protection equipment cost-effective for H1N1 ($23,600 per death prevented)
Personal protection equipment plus restricting visitors and cancelling elective procedures less cost-effective ($2500,000 per death prevented)
Day 2006 Modelling Quarantine Quarantine of all contacts is beneficial only when case isolation is ineffective, significant asymptomatic transmission, and asymptomatic period is neither very long nor short.
Figueroa 2017 Observational Mass gatherings Outbreaks at mass gatherings were uncommon, even during the 2009 H1N1 pandemic
Gostic 2020 Modelling Traveller screening Even under best-case assumptions, screening (at border or locally) will miss more than half of people infected with SARS-CoV-2.
Halder 2011 Modelling School closures
Workplace closure
Antiviral treatment
Household antiviral prophylaxis
Extended antiviral prophylaxis
Combinations were more cost-effective than single interventions; best combination included treatment and household prophylaxis using antiviral drugs and limited duration school closure ($632 to $777 per case prevented)
Halton 2013 Review Surveillance
Contact tracing
Isolation and quarantine
Contact tracing and progressively earlier isolation of probable SARS cases were associated with control of the SARS outbreak.
Handel 2006 Modelling Hypothetical interventions Interventions before vaccines are available must be balanced with potential gains of future vaccines or potential multiple outbreaks.
Hellewell 2020 Modelling Contact tracing Highly effective contact tracing and case isolation enough to control a COVID-19 outbreak within 3 months. Transmissibility is an important factor (when Ro = 2.5, 80%+ contacts needed to be traced and isolated). Timing is also important (5 initial cases, 50%+ chance of achieving control, even at modest contact-tracing levels; however, 40 initial cases, control much less likely). Delays from symptom onset to isolation decreased the probability of control.
Herrera-Diestra 2019 Modelling Vaccination Vaccinating (or self isolating) based on the number of infected acquaintances is expected to prevent the most infections while requiring the fewest intervention resources.
Ishola 2011 Review Mass gatherings Some evidence to indicate that mass gatherings may be associated with an increased risk of influenza transmission
Jackson 2014 Review School closures School closures are most effective when they cause large reductions in contact, when the basic reproduction number is below 2, and when attack rates are higher in children than in adults
Jefferson 2011 Review Screening at entry ports
Isolation
Quarantine
Social distancing
Barriers
Personal protection
Hand hygiene
Overall masks were the best performing intervention across populations, settings, and threats
Lee 2009 Review Antivirals
Antibiotics
Vaccination
Case isolation
Quarantine
Personal hygiene measures
Social distancing
Travel restrictions
Combinations delayed spread, reduced the overall number of cases, and delayed and reduced peak attack rate more than individual strategies.
Lee 2011 Modelling Hand hygiene
Disinfectant measures
Patient isolation
Personal protection equipment
Staff exclusion policies
Ward closures
Implementing increased hand hygiene, using protective apparel, staff exclusion policies, or increased disinfection separately or in bundles provided net cost-savings, even when the intervention was only 10% effective in preventing further norovirus transmission. Patient isolation or ward closure was cost-saving only when transmission prevention efficacy was very high (≥90%), and their economic value decreased as the number of beds per room and the number of empty beds per ward increased.
Lee 2010 Modelling Vaccination Vaccination priority should be given to at-risk individuals and to children within high-risk groups
Li 2013 Modelling Quarantine of close contacts Quarantine in Beijing during 2009 H1N1 reduced confirmed cases by a factor of 5.6; given that H1N1 was mild, “not economically effective”.
Lin 2010 Modelling Social distancing
Case isolation
Supports early containment; the best strategy depends on the transmission characteristics of virus, the state of the pandemic, and the cost and implementation levels of intervention.
MacIntyre 2019 Modelling Case isolation
Contact tracing
Outbreak controlled in 100 days when 95% of cases isolated and 50% of contacts traced.
MacIntyre 2015 Review Face masks Face masks provide protection against infection in various community settings
Markel 2007 Observational School closures
Isolation or quarantine
Public gathering ban
Cities that implemented interventions earlier had greater delays in reaching peak mortality (Spearman r=−0.74, P<0.001), lower peak mortality rates (Spearman r=0.31, P=.02), and lower total mortality (Spearman r=0.37, P=.008). A significant association between increased duration of interventions and a reduced total mortality burden (Spearman r=−0.39, P=.005).
Martinez 2014 Modelling School closures
Workplace closures
Case isolation
Household quarantine
School closure was the single most effective intervention; combination of all interventions was most effective.
Mateus 2014 Review Travel restrictions Evidence did not support travel restrictions as an isolated intervention for the containment of influenza.
Nguyen 2018 Modelling Vaccination Vaccination should be administered 5 months before to 1 week after the start of an epidemic.
Pan 2020 Observational Traffic restrictions
Cancellation of social gatherings
Home quarantines
Designated hospitals and wards
Personal protective equipment
Increased testing capacity
Quarantine of presumptive cases
Quarantine of confirmed cases and of their close contacts
Traffic restrictions, cancellation of social gatherings, and home quarantines are associated with reduced transmission, but not sufficient to prevent increases in confirmed cases. Ro reduced below 1 only when all interventions are implemented.
Pasquini-Descomps 2017 Review School closures
Disease surveillance networks
Contact tracing and case isolation
Face masks
Preventive measures in hospitals
Antiviral treatment
Antiviral prophylaxis
Vaccination
Stockpiling antiviral medicine
quarantining confirmed cases at home
Self-isolation at home
The most cost-effective interventions were disease surveillance networks and contact tracing and case isolation; the least cost-effective intervention was school closure.
Perlroth 2010 Modelling School closures
Quarantine of infected individuals
Child social distancing
Adult social distancing
Antiviral treatment
Antiviral prophylaxis
Combinations were more cost-effective than single interventions; the best combination included adult and child social distancing, school closure, and antiviral treatment and prophylaxis ($2700 per case).
Prosser 2011 Modelling Vaccination Incremental cost-effectiveness ratios ranged from $8000 to $52,000 per quality-adjusted life year for persons aged 6 months to 64 years without high-risk conditions
Rainey 2016 Review Mass gatherings Mass gathering-related respiratory disease outbreaks were relatively rare between 2005 and 2014 in the US, suggesting low transmission at most types of gatherings, even during pandemics
Rashid 2015 Review School closures School closures moderately effective in reducing influenza transmission and delaying epidemic peak; associated with very high costs
Ryu 2020 Review Travel restrictions Evidence does not support entry screening as an effective measure.
Sang 2012 Modelling Quarantine
Isolation
Entry travel screening
Isolation was the best strategy; entry screening delays the peaks but does not prevent the epidemic.
Saunders-Hastings 2017 Modelling School closure
Community-contract reduction
Hang hygiene
Face mask
Voluntary isolation
Quarantine
Vaccination
Antiviral prophylaxis
Antiviral treatment
Vaccination plus antiviral treatment most cost-effective (cost per life-year saved: $2581); however, it still led to 3026 life-years lost. Only 1607 life-years lost at a marginally higher cost ($6752) with combination including community-contact reduction, hand hygiene, face masks, voluntary isolation, and antiviral therapy. Combining all interventions saved most lives (267 life-years lost), but very costly ($199,888 per life-year saved).
Saunders-Hastings 2017 Review Hand hygiene
Face masks
Hand hygiene significant protective effect (OR = 0.62; 95% CI 0.52–0.73).
Face masks non-significant protective effect (OR = 0.53; 95% CI 0.16–1.71) (randomized control trials and cohort studies)
Face masks significant protective effect (OR = 0.41; 95% CI 0.18–0.92) (randomized control trials and cohort studies pooled with case–control studies)
Schiavo 2014 Review Communicating health risk
Promoting disease control measures
Evidence not conclusive
Shi 2010 Modelling Mass gatherings Mass gatherings that occur within 10 days before the epidemic peak can result in a 10% relative increase in peak prevalence and total attack rate; little effect when occurring more than 40 days earlier or 20 days after the infection peak (when initial Ro = 1.5)
Shiell 1998 Modelling Vaccination Vaccinating all unvaccinated school-aged children was the most cost-effective strategy ($32.90 marginal cost per case prevented).
Smith 2015 Review School closure
Quarantine
Social distancing
Oral hygiene
Hand hygiene
Face masks
Social gatherings
Positive significant interventions included professional oral hygiene intervention in the elderly and hand washing.
Suphanchaimat 2020 Modelling Vaccination Incremental cost-effectiveness ratio of vaccination (compared with routine outbreak control) $1282–$1990/DALY.
Townsend 2017 Modelling Hand hygiene National behaviour change programme would net $5.6 billion (3.4–8.6) in India and $2.64 billion (2.08–5.57) in China
Tracht 2012 Modelling Face masks $573 billion saved if 50% of the US population used masks in an unmitigated H1N1 epidemic
Tuncer 2018 Modelling Isolation
Quarantine
Education
Safe burial
Social distancing
Social distancing had the most impact on the 2014 Ebola epidemic in Liberia, followed by isolation and quarantine.
Van Genugten 2003 Modelling Vaccination
Antiviral treatment
Similar results from vaccinating the entire population vs. only at-risk groups; best strategy combined pneumococcal vaccination of at-risk groups and antiviral treatment.
Velasco 2012 Review School closure
Antiviral prophylaxis
Social distancing
Vaccination
Quarantine
Combinations were more cost-effective than vaccines and/or antivirals alone; reducing non-essential contacts, using pharmaceutical prophylaxis, and closing schools was the most cost-effective combination.
Viner 2020 Review School closures School closures did not help the control of the 2003 SARS epidemic in China, Hong Kong, and Singapore and would prevent only 2–4% of COVID-19 deaths
Young 2019 Modelling Isolations and quarantines Case isolation is likely ineffective when the identification of infected hosts is not sufficiently thorough or delayed.
Zhang 2015 Modelling Voluntary self-isolation
Antivirals
Voluntary self-isolation at symptom onset can achieve the same level of effectiveness as starting antiviral prophylaxis; when delayed 2 days, strategy has a limited effect on reducing transmission.
Zhang 2012 Observational Border screening
Close contact tracing (and quarantine)
Medical follow-up of international travellers
Influenza-like illness monitoring
Border screening: 132/600,000 (0.02%) people infected; contact tracing: 120/4768 (2.5%) infected; medical follow-up of international travellers: 18/346, 847 (0.005%) infected; influenza-like illness monitoring: 339/180,495 (0.2%) infected.
Zhao 2020 Observational Domestic travel Each increase of 100 in daily new cases and daily passengers departing from Wuhan was associated with an increase of 16.25% (95% CI: 14.86–17.66%) in daily new cases outside of Wuhan.