Tough tests for Covid-19
Image credit: PA
With a Covid-19 vaccination reckoned to be at least 18 months down the track, testing remains one of the most important options for combatting the pandemic.
“We have a simple message for all countries. Test, test, test. Test every suspected case.” These are the words of Dr Tedros Adhanom Ghebreyesus, director-general of the World Health Organization (WHO), who in March 2020 declared the outbreak of respiratory disease Covid-19 to be a pandemic.
Critical of international governmental response to the crisis, the public face of WHO said: “We have not seen an urgent enough escalation in testing, isolation and contact tracing, which is the backbone of the response. And to do that, you must test and isolate. You cannot fight the fire blindfolded.” Neither can significant inroads be made into arresting the pandemic, stressed Ghebreyesus, “if we don’t know who is infected”.
With an estimated 1.7bn people around the world being told to stay at home, a fifth of the global population is living under some form of pandemic containment strategy. Even at their most effective, such strategies can only slow the spread of the disease, leaving the public wondering when there will be a vaccine. While there is plenty of good news on this front in the form of biotech companies and academic institutions worldwide rushing to create one, the harsh reality is that bringing a vaccine through regulatory approval can take as long as a decade.
According to vaccinologist Annelies Wilder-Smith, the pandemic “will probably have peaked and declined before a vaccine is available”. Wilder-Smith, who is professor of emerging infectious diseases at the London School of Hygiene and Tropical Medicine, doesn’t think that “this vaccine will be ready before 18 months”, which makes Donald Trump’s announcement that there will be a vaccine ready by the 2020 presidential election on November 3 seem to be based more on political swagger than scientific probability.
Even if approval for a vaccine could be fast-tracked to be ready in this compressed timeframe, this is only one step on a critical path that sees two major challenges further down the line in the form of manufacture and distribution. Author of ‘The End of Epidemics’, Jonathan Quick says that when it comes to a global immunisation programme, “virus biology and vaccines technology could be the limiting factors, but politics and economics are far more likely to be the barrier to immunisation”.
Which makes the WHO’s exhortation to “test, test, test” one of the strongest weapons in the armoury for fighting the spread of Covid-19. While the general sentiment of ‘if it moves test it’ makes all the right noises, with the aviation industry seen as a vector for spreading the coronavirus around the world, a key focus has been on exit and entry screening at international airports.
Non-contact infrared thermometers (so-called ‘temperature guns’) at airports are nothing new, having been used, for example, during the 2016 Ebola virus disease epidemic, but their effectiveness in detecting Covid-19 remains unclear. Critics of the thermometer guns maintain that while health officials wielding scientific instruments may look reassuring, their impact is marginal. This is a view held by epidemiologist at the University of Hong Kong Ben Cowling, who says “ultimately, measures aimed at catching infections in travellers will only delay a local epidemic and not prevent it”. He also voices the opinion that such measures are often instituted to serve as a visual confirmation that the authorities are “doing something”.
The limitations of remote temperature sensing mean that people carrying the virus inevitably slip through the net. According to the EU Health Programme, the biggest shortcoming of hand-held thermometers is that they measure skin temperature. This does not necessarily reflect core temperature, which is a key metric for fever detection. While it is possible that passengers taking fever-suppressing medication may produce false negatives, of more concern is that infected people in the incubation phase (for Covid-19 this can be up to 14 days) can be asymptomatic, with the result that temperature guns won’t raise the flag required for passengers to be taken for secondary screening.
Despite the dramatic fall in air travel (at the time of writing figures from the International Air Transport Association indicate a 19 per cent loss of passenger revenue equivalent to $113bn) airports remain an obvious weak link in the global spread of Covid-19. According to the American Association for the Advancement of Science “experience with other diseases shows it’s exceedingly rare for screeners to detect infected passengers. Just last week [early March], eight passengers who later tested positive for Covid-19 arrived in Shanghai from Italy and passed the airport screeners unnoticed. Even if scanners do find the occasional case, it has almost no impact on the course of an outbreak.”
A case in point is the US entry screening of citizens, permanent residents and families returning from China. The programme started on 2 February and within three weeks 46,016 air travellers had been screened, with just one testing positive. By 27 March figures collated by the Johns Hopkins University revealed that with more than 85,000 positive tests the US had overtaken China. The White House explained the rise in numbers as a function of the US increased testing programme, which stands at just over half a million.
‘The one thing that is worse than no test is a bad test’
For the time being, at least, best practice exists predominantly in the form of regulatory guidelines rather than technology implementation. Singapore has recently introduced an ambitious auditing scheme to increase resistance to the pandemic in sectors where there is heavy human traffic. There is no word yet about how a small nation that is heavily economically dependent on overseas visitors is planning to implement screening technology.
Public Health England, an executive agency sponsored by the Department of Health and Social Care, describes ‘extra measures’ at UK airports as not including temperature screening of passengers. “Instead, we are providing airlines and airport operators with posters and leaflets with the latest advice, symptoms and what to do if passengers get them.” ‘Enhanced monitoring’ is in place for all flights from areas affected outside Europe and includes leaflets for passengers, but no test-based screening. Reports of chaos at international airports attempting to screen travellers include stories of how at Chicago O’Hare and at Dallas-Fort Worth Airports the concept of social distancing became meaningless as large crowds formed to wait five hours for a nurse to take their temperature. One traveller was quick to draw attention to the risk: “After being on a plane where everyone was packed tightly in it felt like they were encouraging the disease to spread rather than doing anything to curb it.”
As major economies start gearing up for a relaxation, however slight, of containment measures – Donald Trump was bullish in wanting the US “opened up” by Easter, while the UK’s plans to review its situation at the same time were put on hold as Prime Minister Boris Johnson was hospitalised with the virus – all eyes are turning to the role testing for Covid-19 will play in the immediate future. In the UK, Professor Sharon Peacock, director of the National Infection Service for Public Health England, told MPs that 3.5 million tests had been ordered and would be available in the near future. “Several million tests have been purchased. These are brand new products. We have to be clear they work as they are claimed to do. Once we are assured that they do work, they will be rolled out into the community.” Currently no country has a comprehensive nationwide test programme.
However, the UK’s Chief Medical Officer Professor Chris Whitty has warned that these ‘finger prick’ tests will not necessarily be available to the public to buy, as priority will be given to key workers, such as NHS staff currently in self-isolation, in order to assess their fitness to return to work.
While finger-prick tests are not expected to be 100 per cent accurate, Boris Johnson is calling them a “game changer”. Whitty went on to say: “I do not think that this is something we will suddenly be ordering on the internet next week. We need to go through the evaluation, then the first critical uses, and then stretch it out from that point of view. We need to do that in a systematic way. The one thing that is worse than no test is a bad test.”
Meanwhile, biotech companies around the world are taking up the challenge to develop more reliable and time-efficient tests. Scientists from the University of Oxford’s Engineering Science Department and the Oxford Suzhou Centre for Advanced Research have announced a rapid testing technology that could produce results in as little as 30 minutes (more than three times faster than current methods). Co-team leader Professor Wei Huang says that “the beauty of this new test lies in the design of the viral detection that can specifically recognise SARS-CoV-2 (Covid-19) RNA and RNA fragments. The test has built-in checks to prevent false positives or negatives and the results have been highly accurate.” Huang say that the test is also highly sensitive, which will increase the potential for patients in the early stages of infection to be identified sooner.
The scientists at Oxford are now working to develop an integrated device that would allow the test to be taken into the field, with airports an application under review. It’s early days, but Huang says that there are plans for putting these kits into production.
It’s a fast-moving landscape, one in which the agility of biotech start-ups will play a significant role, with organisations such as the Apple-backed Mammoth Biosciences using Crispr (clustered regularly interspaced short palindromic repeats) gene-editing technology to come up with faster and more accurate results. While Crispr is more usually associated with the treatment of rare genetic diseases, Mammoth Bioscience’s CEO Trevor Martin says that Covid-19 testing is also “exactly what Crispr technology is meant to help with – rapid response to infectious diseases”.
As the pandemic becomes a ‘new reality’ for the planet’s population, in an uncertain world one thing is certain: the science and technology community has never been under more pressure to come up with the goods.
Singapore prepares for post-Covid-19 future
Singapore’s senior minister for trade and industry has announced that more than 37,000 businesses associated with the tourism and lifestyle industry are “being encouraged” to sign up to a nationwide health quality mark programme. Called ‘SG Clean’, the move is intended to increase confidence in sectors with daily heavy human traffic, including shopping malls, hotels, tourist attractions, conference venues, schools and transport nodes.
Backed by the ministries of transport and education, as well at the Public Hygiene Council, the certification programme is being seen as a reinforcement of current best practice, while preparing the tourism sector for a post-restriction return to business. With the country annually attracting as many as 20 million overseas visitors – more than three times its national population – the tourism sector is critical to the economy, with tourism receipts accounting for as much as 4 per cent of the national economy.
“Over the next two months we intend to audit and certify 570 hotels,” says Keith Tan, CEO of the Singapore Tourism Board. “The SG Clean quality mark sends a strong signal to both locals and visitors that we take hygiene seriously and are committed to maintaining these high standards as a ‘new normal’ for the future.”
The certification process is based on a seven-point set of thresholds that include the appointment of an SG Clean manager to oversee an establishment’s practices, temperature and health screening of employees, revised protocols for engagement with external personnel such as suppliers and contractors, and compliance with health and travel advisories, guidelines and government orders on Covid-19.
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