Testing for the coronavirus (COVID-19)

Testing for the coronavirus (COVID-19) has varied widely across countries. To reduce the risk of new outbreaks, countries will need to greatly increase their testing capacity. 


A  key  question  behind  any  strategy  to  ease confinement  restrictions  and  reopen  economic activities is how to avoid a new spread of the SARS-CoV-2 virus that would necessitate further lock downs.  Once the  number  of  infected  people  has  successfully  been  brought  sufficiently down, quick  suppression  of new  waves  of  viral  infections  will  be  key.  Testing  strategies  are central to achieve this.

There are two types of tests.

First, molecular diagnostic testing (RT-PCR) helps to identify those individuals who are infected at the time of the test. An effective strategy that tests, tracks people infected and traces their contacts (TTT), helps to reduce the spread of the virus and thus bring its reproduction number below one.
Given the characteristics of this coronavirus–including the large number of asymptomatic cases and high reproduction number –to be effective at suppressing the spread of the virus, the TTT strategy should be used very widely, requiring a very large proportion of all cases (between 70 and  90%) to be traced to  prevent  a new outbreak of the  virus. This  would require increasing capacity for testing enormously; putting in places trict measures to prevent people who may be infectious from breaking quarantine; as well as identifying ways to trace contacts,which may push the limits of privacy concerns, unless new approaches to digital tracing, currently under development, are put in place.
Significant logistics and capacity constraints –ranging from the availability of trained personnel to  take  accurate  specimen,  to  the  time  required  for  laboratory  analysis  and  the  availability  of reagents –have impeded more widespread diagnostic testing in many countries so far. Recent development of faster RT-PCR molecular diagnostic testing, which can be deployed at the point of care, should help scale-up capacity for  effective TTT in countries. Digital  enabled contact-tracing can  help  improve  the  speed  and  effectiveness  of  TTT  strategies,  as  seen  in  some countries.

A second type of test –so-called serologic test –detects people who have had a prior infection and  thus  developed  antibodies.  Such  tests  can  be  used  for  two  purposes,  namely  to  allow people who have acquired immunity to return to work safely, and to provide intelligence on the evolution of the epidemic across the population. Rapid serology test kits need to be developed and  their  clinical  performance  needs  to  be  demonstrated  before  deployment  at  scale  can happen.
Despite the fact that a relatively low number of people have so far been infected and thus we are still far from herd immunity, the successful implementation of serologic testing strategies at large scale can help reduce the spread of the virus and complement the TTT strategy.

This will also require major efforts, including: 

1) verifying the clinical performance of tests, particularly for rapid  serologic  tests; 

2) preparing  procurement  and  logistics  arrangements  to  scale  up production and deployment of the tests, and train and deploy human resources, particularly for diagnostic RT-PCR tests; and

3) providing adequate safeguards to protect civil right and privacy of populations while deploying or apps-enabled tracking strategies.

Since the end of last year, the world has been in the grip of the SARS-CoV-2 virus, which has caused tens of thousands of deaths from the respiratory disease COVID-19. To combat the pandemic, many countries have put in place strict containment and mitigation strategies to minimise the risk of transmission, decrease the spread of the virus and ‘buy time’ for health care systems to cope with the huge numbers of patients and ultimately save as many lives as possible. As part of the response to COVID-19, virtually all OECD countries affected by the virus have introduced strict restrictions to social and economic life, including social distancing and even full lock downs. The big question  is  now  how  to  manage  these  restrictions,  and  how  to  go  back  to  a new  normal of  living  with SARS-CoV-2; a social and economic life that coexist with the virus. To avoid new peaks in the number of cases, overstretching health system capacities, infection rates need to remain suppressed until a vaccine or  effective  treatment  are  found.  If  all  confinement  strategies  are  lifted,however,  the  infection  rate  is expected to rebound in a matter of weeks. A strategy is needed about when and how to relax confinement, and when and how to re-tighten some of them when necessary. This is needed to minimise the risk of further peaks of the outbreak or, at least, to win as much time as possible between the successive peaks.

A number of factors need to be in place to achieve this goal. 

First, healthcare capacity and resources need to be increased to ensure safe and effective management of future severe COVID-19 cases.

Second, we need to understand the virus better, including: the incubation period and infectiousness of the disease  at  different  stages;  the  extent  of  asymptomatic  spread;  immunity  and  its  duration  in  those  who contracted the virus; and the impact of changes in temperature on the disease spread.

Third –and the topic of this brief –information about the presence and propagation of SARS-CoV-2 in the population  needs  to  improve  significantly. For  this,  widespread  testing  and  effective  contact  tracing, including cases with no or only mild symptoms, are key components of the post-lock down strategy. Better information will help achieve three goals:

Tracking of new cases to suppress the resurgence of local outbreaks as early as possible, aiming to avoid new peaks;

Identifying previously infected people who can safely return to work, to revitalise the economy and to strengthen the health workforce;

Gaining  intelligence  on  the  evolution  of  the  epidemic,  including  on  when a  threshold  for herd immunity has been reached.In the case of COVID-19, it has been estimated that 50% to 60% of the population needs to be immune to the virus to halt its spread.

The Organisation for Economic Co-operation and Development (OECD) is an international organisation that works to build better policies for better lives. Together with governments, policy makers and citizens, work on establishing evidence-based international standards and finding solutions to a range of social, economic and environmental challenges. From improving economic performance and creating jobs to fostering strong education and fighting international tax evasion, provide a unique forum and knowledge hub for data and analysis, exchange of experiences, best-practice sharing, and advice on public policies and international standard-setting.


More info at: Tackling coronavirus (COVID‑19)
Contributing to a global effort


Zeljko Serdar, CCRES

PS.
The OECD Teaching and Learning International Survey (TALIS) is an international, large-scale survey of teachers, school leaders and the learning environment in schools. This note presents findings based on the reports of lower secondary teachers and their school leaders in mainstream public and private schools. CROATIA