HOW TO WIN AT SNAKES AND LADDERS - WHO World Health .

Preventing transmissionlaboratories would be co-located, as inhospitals and in some South Korean drivethrough testing sites. This is a ladder,although one that is rare in communitytesting sites in Europe. The ultimate goalis to develop a test that does not requirea laboratory, using a point of care testthat can produce immediate results,particularly for those without symptoms,but those that have been developed sofar have not performed sufficiently wellto depend on at population scale. Thisapproach also removes the need forlaboratories, which are a critical ratelimiting step in any pathway at populationscale. So far, cases that are confirmedthrough rapid testing usually have to beverified through PCR swab testing andso this approach is still only likely to befeasible at a low prevalence. Estonia hasalso offered an innovative approach, usingdrones to deliver some samples directly tolaboratories. In the UK, most testing takesplace in just seven commercial megalaboratories, creating transport bottlenecksand reports of discarded samples.Given the evidence that symptomatictesting alone is likely to miss a largeproportion of infectious presymptomaticand asymptomatic cases, 6 7 there hasalso been a move more recently towardsregular mass testing in high risk settingssuch as in health and social care settingsand areas of increased transmission inLithuania and England. It remains unclearhow regular such testing needs to be tobe effective but some studies suggest aninterval of two days is required, 8 whichis likely unfeasible for RT-PCR testing.Others, including Estonia, France, Icelandand Germany have also instituted testingfor incoming travellers, although theirtesting policies and capacity differ. Asecondary but important concern forasymptomatic screening is that it doesnot help to identify which of the caseswill be most likely to transmit the virusto others, given that very few cases seemto be responsible for a large proportionof transmission, otherwise known asclustering 9 and that RT-PCR can pickup both infectious and non-infectiouscases. Germany and Portugal are alsonow testing samples in batches, so calledpooled sampling, 10 taking lessons fromthe population screening programme inWuhan and from HIV testing strategies. 1137Any mass testing in high risk settingsmust also be done under the strictest ofinfection control precautions to preventcross contamination, which can lead tofalsely positive results. A second typeof pooling is surveillance sampling ofwastewater, which has also been shownto be a useful early warning system tomonitor outbreaks 12 and the utility ofthis approach is now being studied by theEuropean Commission in a number ofEuropean countries.Strengthening lab capacity to rapidlyanalyse samples and immediatelyreport the resultsThe ability to scale up testing willbe easier in countries that havehad sustained investment in healthinfrastructure, including laboratoryequipment, technicians, logisticssystems, and information technology.Germany 13 entered the pandemic with astrong diagnostics and chemicals industry,which allowed it to implement large scaletesting rapidly. 14 In contrast, the UK didnot. Thus, a lack of sufficient laboratorycapacity is another snake that will createsevere delays in processing tests, possiblyrequiring substantial re-testing whichexacerbates an already difficult situation.include accelerated training of laboratorytechnicians, as in Israel, or use of robots,as in Denmark.While there is widespread agreement thattests should be conducted within a country,where possible, debate continues as to theother approaches. Countries adopting thefirst one do generally appear to have beensuccessful and although Germany hasstruggled to meet demand more recentlyrationalising its testing programme of allincoming travellers to those from highrisk countries, demand for tests in theUK is reported to be many times capacityas laboratories have struggled to keeppace, with the Prime Minister calling onuniversity laboratories to redeploy staff tothe lighthouse laboratories once again, andresorting to sending more samples abroad.‘‘contacttracing is a corecomponent ofpublic healthOnce samples are processed, automatedreporting can create a ladder, helping toWhere laboratory capacity is insufficient, deliver results quickly to cases and contacttracers who will be able to initiate tracingthree types of response can be seen. Onesooner. There are numerous examplesinvolves expanding existing medicallaboratories or repurposing others, such as of countries where this is working,including Belgium, Estonia, Iceland,those involved in veterinary surveillanceTurkey and Lithuania. Rapid initiationin universities, as in Croatia, Cyprus,Estonia, France, Germany, Lithuania, and of contact tracing will reduce the risk offurther transmission. It also increases theNorway, among others. Thus, Germany 13rapidly commissioned testing in 300 local likelihood that suspected cases will agreelaboratories and Sweden also used existing to isolate while they wait for their results.Without an automated system, results havelaboratories in all but 2 of its 21 regions.to be telephoned individually to cases,A second involves creation of a fewwhich is resource intensive and can delaycentralised mega-laboratories. In the UK,notification and isolation. Some countriesoutsourcing companies, many with littlesuch as the UK are also planning toor no experience of running laboratories,implement mass point of care testing andwere contracted to construct a few largeit is unclear how this critical component oflighthouse laboratories, creating a highlycentralised system. A third approach, seen automating results will be factored in.in Ireland and Finland, involved samplesSelf-evidently, there must be a system tobeing sent abroad for testing, althoughmonitor test performance to ensure falseas the UK has found, if samples are sentpositives and negatives are minimised.abroad at the wrong temperature theyThis may create logistic challengescannot be processed and will be voided.for quality assurance where new orOther measures that also contributerepurposed laboratories have come onEurohealth — Vol.26 No.2 2020

38stream, although there are examples, suchas those in Italy and Ireland, that can offerlessons. Further guidance is now requiredon how to standardise laboratory testingin different labs using different assays andmachines. Quality assurance is criticaland mechanisms to monitor this wereimplemented in Italy and Ireland.Building a large, well-trainedworkforce to conduct contact tracing(even in countries using digitaltechnologies)Despite renewed attention, contacttracing is a core component of publichealth departments, which have longexperience in preventing transmissionof other communicable diseases suchas tuberculosis, hepatitis, and sexuallytransmitted infections. Contact tracingrequires a well-resourced existing publichealth infrastructure, with a trainedworkforce that is well connected withlocal services. Such a system will enableclusters and complex outbreaks to bedetected early. This is an important ladderthat will help to strengthen the FTTIprocess and is crucial for any containmentor mitigation strategy. Various strategieshave been used to trace contacts, outlinedelsewhere 15 (also see the article byHernández-Quevedo, et al. in this issue)but each case must be interviewed toensure that they isolate, identify, and riskassess their contacts, providing sufficientinformation to locate and engage withthem. An inadequate number of contacttracers creates a snake as manual contacttracing is time consuming, demandinga large workforce. Any delays will leadto increased transmission. Modellingsuggests that around 80% of nonhousehold contacts would have to betraced and isolated within 48 hours of thefirst person experiencing symptoms, withstrict adherence to self-isolation and thereare few examples of countries in Europewhere this is happening systematically. 16To avoid this snake, several countries haverecruited paid contact tracers to work incall centres, including France ( 8,000),the UK (18,000) and Germany (up to fivecontact tracers per 20,000 inhabitants),although an early survey in Germanyshowed that only 24% of departmentsEurohealth — Vol.26 No.2 2020Preventing transmissionwere able to meet this target in mid-Mayand it is unclear what proportion willbe experienced contact tracers. Thereare various ways to boost the contacttracing workforce. They include invitingexperienced environmental health officers,sexual health specialists, and retireddoctors and nurses, as the UK has done(although uptake is unknown and inreality this kind of redeployment can onlyever be temporary to avoid neglectingother serious health problems). Othershave recruited military personnel (as inGermany and Israel) and medical students(as in Finland), or recruited volunteers (asin Cyprus). However, in all cases, therecan be challenges in ensuring that they areall adequately trained.‘‘support necessary upgrades in hardwareand software and France has also investedin improved contact tracing software.In contrast, 16,000 cases were recentlymissed in the UK because of a relianceon outdated Microsoft Excel templatesto transfer data. In many countries,(including Austria, Belgium, Croatia,Estonia, France, Greece and Ukraine)primary care services are also involvedin the test, trace, isolate process andcan monitor and support cases moreeffectively.Supporting people in isolation (unlessyou want to start the game again)Isolation is arguably the most importantpart of the test, trace isolate processaccording to recent evidence. 18 A team ofcommunity volunteer contact tracers inthe UK published data 19 from a pilot inwhich it took approximately 80 minutesto manage each case, with many contactswere unwilling to isolate. Crosssectional data from May also suggestedthat only 25% of those with householdThere has been considerable attentionsymptoms of COVID-19 in the UKon digital technology, specificallyactually adhered to isolation guidance. 20apps as a potential ladder, given theirMeasures to support isolation are thereforepotential to identify and notify contactsan important ladder and in Denmark,quickly. Countries where they haveFinland and Lithuania, people who cannotbeen implemented include Austria,isolate are accommodated elsewhereBelgium, Bulgaria, Canada (Alberta),(albeit for a fee in Finland). The sameDenmark, Finland, France, Georgia,approach has also been used successfullyIceland, Ireland, Italy and Germany,to prevent outbreaks in care homeswhere the Corona-Warn-App has beeni

Journal of the Royal Society of . their speed and direction influenced by a multiplicity of factors, many outside their control. Practically, however, if we are to help the busy policymaker, we must simplify this considerably, something that we have done by portraying the main elements of the system as a Snakes and Ladders boardgame (image). Snakes and Ladders is remarkably well suited to .