Could Australia and New Zealand take advantage of international travel distances and emergent technology to detect future pandemics early?
Australia and New Zealand are located in the 'Oceania' region of world and within this a sub-region called Australasia. Geographically, this area is located with the South Pacific Ocean to the East and the Indian Ocean to the West.
Australia and New Zealand were discovered by European explorers relatively late in 1642 and 1606 respectively. Before this, the first nations populations in each country had settled the lands for hundreds if not thousands of years. A key reason for the relatively late discovery of both countries by European explorers was simply the remoteness of the Australasian land masses. New Zealand and Australia are located around 17,800 km and 14,092 km respectively from Europe.
After rapid European settlement through the 19th and 20th centuries in Australia and New Zealand, trade with the old world grew with the likes of fur, whale oil, meat, dairy and other agricultural products. It was this trade and the perilous journey European immigrants underwent to migrate to the antipodes that the 'tyranny of distance' became the long standing hurdle the British colonies needed to endure to retain connections with 'mother England'.
A smaller world - international connectivity
The last decades have seen a rapid increase in the levels of international connectivity and Australia and New Zealand are no exception. The International Air Transport Association (IATA) estimates global airlines carried 1.6 billion passengers in 2000, 2.1 billion by 2005, and 3.5 billion passengers by 2015.
Prior to the COVID-19 pandemic, international passenger numbers were projected to reach 10.5 billion passengers by 2023. The actual volume of global passengers in 2023 ended up being around 8.6 billion passengers, which was 94 % of 2019 levels. In terms of flights, the volume went from 23.8 million flights in 2004 to 38.4 million in 2023 (with a low of 16.9 million in 2020).
The downsides of connectivity
With this rapid increase in connectivity came inevitable downsides. This included the rise of transnational crime, illegal immigration, bio-security risks, exploitative tourism, and the negative impacts upon the environment.
...arguably all of the risks associated with increased international connectivity are over-shadowed by those associated with public health...
This was first highlighted with the outbreaks of the Severe Acute Respiratory Syndrome (SARS) coronavirus in late 2002; the influenza virus, labelled H1N1 and commonly referred to as the 'swine flu' spread in 2009; the Middle East Respiratory Syndrome (MERS) in 2012; the severe infectious disease Ebola of 2014; the Zika virus of 2016, and repeated outbreaks of Polio and Malaria over the last decade.
It was however, the emergence of a new strain of coronavirus (COVID-19) from China in late 2019 that had the most significant and enduring global impact and served to highlight the risks of international connectivity.
Once outside China, COVID-19 rapidly travelled through the world and was declared a pandemic by the WHO in March 2020. Governments responded with differing levels of restrictions to stop its spread and limit the death toll. All told, by 2023, the WHO estimated the cumulative death toll to be at least seven million and the World Bank assessed the pandemic it to have caused the worst global recession since World War 2.
Efforts to prepare for the next pandemic
Since COVID-19, governments, companies, organisations, communities and individuals have been actively planning and initiating strategies that could help save lives and reduce the devastating impact of future pandemics. This has included the likes of:
Preparedness and Prevention:
Vaccination programs: Developing and undertaking vaccination campaigns to protect individuals and communities from infectious diseases.
Surveillance systems: Establishing and maintaining surveillance systems to detect and monitor outbreaks early on.
Stockpiling resources: Building and maintaining stockpiles of medical supplies, pharmaceuticals, and equipment to ensure a swift response when needed.
International Cooperation and Coordination:
Global health organizations: Collaborating with international organizations such as the World Health Organization (WHO) to share information, resources, and expertise.
Multilateral agreements: Participating in and supporting agreements that facilitate the sharing of data, research, and resources among countries during a pandemic.
Communication and Education:
Public health campaigns: Conducting public health campaigns to educate the public about the importance of hygiene, vaccination, and other preventive measures.
Clear communication: Ensuring transparent and timely communication of information about the virus, its transmission, and guidelines for the public.
Healthcare Infrastructure and Capacity Building:
Capacity planning: Strengthening healthcare infrastructure and building surge capacity to handle a sudden influx of patients.
Training healthcare workers: Providing training and resources for healthcare workers to respond effectively to a pandemic.
Telemedicine and technology: Utilising technology for remote consultations, contact tracing, and monitoring the spread of the virus.
Aviation industry pandemic planning
Many countries are considering additional mitigation strategies since COVID-19 for future pandemics. This has included new surveillance systems to detect and monitor outbreaks early on. These reviews frequently focus on international airports as the key for future readiness.
In one study, Nieuwborg et (2024) noted the limited readiness of the airport system, how the airport system was running 'behind the facts', the complex relational dynamics within the airport system, the overlay of relationships between public health aviation stakeholders, and the necessity for a systemic approach to sensemaking capabilities. The report highlighted the need to support the airport system's transition (from a pandemic liability) to a strategic asset in mitigating public health disruptions.
Extending border surveillance
The challenges within the airport system, however, are only one component of the international supply chain that could be enhanced to manage the next pandemic. While airport systems are an obvious focal point, there may be opportunity to extend border surveillance for future pandemics. What if the risk of pandemics could be detected before passengers arrived within the bounds of national jurisdiction? This could include:
(1) pre-departure
(2) during the journey, and
(3) upon arrival but pre-border.
As Kamalrathne et al (2023) notes, effective early detection, timely surveillance and early warning - are key aspects of a successful response to an epidemic or pandemic.
Detecting pandemics by testing flight wastewater
In September 2022, the CDC collaborated with Ginkgo Bioworks to evaluate the feasibility of SARS-CoV-2 variant detection in aircraft wastewater from incoming international flights. Wastewater samples were taken from some flights from France, United Kingdom, and the Netherlands, arriving at the International Airport in New York. Wastewater was collected from the planes during maintenance using a device attached to the lavatory service port and the hose for the lavatory service truck.
During August 1–September 9, 2022, eighty samples were tested for SARS-CoV-2 with the result finding 65 samples (81%) were positive. Twenty-seven SARS-CoV-2 genomes were detected in 25 wastewater samples; sequencing quality control criteria were not met for the remaining 40 positive samples. All identified genomes were Omicron and the SARS-CoV-2 genomes identified were consistent with Western European sequences uploaded to the Global Initiative on Sharing Avian Influenza Data (GISAID) at the time.
Overall, this research highlighted the feasibility of aircraft wastewater surveillance as a low-resource alternative to individual testing without direct traveller involvement or disruption to airport operations.
The study showed the key limitations of the technique related to:
the reliance upon passenger use of the toilet during the flight - which has a direct correlation with the duration of the flight.
inability to distinguish travellers with connecting flight itineraries, which lessens precision when ascertaining variant origin; and
potential carryover of residual SARS-CoV-2 RNA between flights yielding viral detections unrelated to travellers on the flight; and
stringent genome coverage thresholds possibly reducing the likelihood of carryover variant identification on subsequent flights.
Another study (Ahmed et al, 2022) aimed to establish whether the surveillance of aircraft wastewater could provide an additional layer of information to supplement (individual) clinical testing. The wastewater of 37 long-haul flights used to repatriate Australians was tested for the presence of SARS-CoV-2 RNA. For this flight, all passengers over 5 years or older were tested for coronavirus 48 h before departure (with only those with a negative result allowed to travel). After the flight to Australia, all passengers undertook quarantine for 14-days.
Subsequent analysis of the wastewater from 24 (64.9 %) of the 37 flights tested positive for SARS-CoV-2 RNA. This resulted in further clinical testing (during quarantine) identifying 112 cases of COVID-19 and showed a positive predictive value (PPV) of 87.5 % and 83.7% accuracy for COVID-19 cases during the quarantine period. The study hence highlighted how surveillance of wastewater from aircraft could be a helpful tool for informing the detection and monitoring of pathogens, and management of travellers.
Detecting pandemics at international arrival terminals
Farkas et al (2023) sought to detect SARS-CoV-2 in sewage taken at the arrival terminals of three international airports in the UK (Heathrow, Bristol and Edinburgh). The sewage samples were also taken from trucks responsible for removing wastewater from the aircraft. Most samples from both the planes and the terminals contained high concentrations of SARS-CoV-2, suggesting there were many people unwittingly bringing COVID back to the UK.
Like other research on airport surveillance, this project confirmed numerous passengers entering the UK were carrying SARS-CoV-2. In this case, all passengers arriving would have had to take a pre-departure test. These cases may not have been caught because the infection was in its early stages when they were first tested, because the testing failed or because they contracted COVID while in transit.
Distance an advantage for Australia and New Zealand?
Given the proven value of wastewater detection for future pandemics - could the long flight times become an advantage for Australia and New Zealand?
By way of example - for New Zealand, the nearest direct flights into the country are around 3 hours from the east coast of Australia, around 12 to 19 hours from America and Canada, to up to 24 hours or more from the UK/Europe. To break this down further:
For North/South America destinations to New Zealand:
Los Angeles to Auckland: 13 hours
Vancouver to Auckland: 14 hours
Honolulu to Auckland: 9 hours
Houston to Auckland: 14h30mins
Chicago to Auckland: 16 hours
Buenos Aires to Auckland: 12h30mi
From Asian destinations to New Zealand:
Singapore to Auckland: 10h30mins
Hong Kong to Auckland: 11 hours
Dubai to Auckland: 16 hours
Bangkok to Auckland: 12h30min
Tokyo to Auckland: 11 hours
Mumbai to Auckland: 16h30mins
From UK/European destinations to New Zealand:
London to Auckland: 24 hours
Frankfurt to Auckland: 23h30mins
Stockholm to Auckland: 25h30mins
Dublin to Auckland: 28 hours
Zurich to Auckland: 23 hours
Australian flights times to comparable destinations are similar to New Zealand with variations depending on which direction the flight originates (i.e. Australia is closer to Asian destinations and further away from the American destinations).
The challenge of incomplete coverage
All the research undertaken found that testing the wastewater of air travel passengers does have limitations. Primarily, that not every passenger will use the toilet on the plane. Specialists (Medical News Today) estimate that most people urinate between 6 – 7 times in a 24 hour period, but anywhere between 4 and 10 times a day can also be normal.
Some estimates hence suggest that on an average long-haul flight (6 -12 hours<), around 50 -80% of passengers will use the toilet at least once based upon an average of one (toilet) visit every 3 hours per person. This could mean passengers use the toilet approximately 2-3 times during the flight and hence around 70-80% of passengers overall. In the Farkas et al (2023) study, however, only 13% of passengers on short-haul flights and 36% of those on long-haul flights were likely to require the use of the toilet on the plane.
Despite these variabilities, there is no doubt that a significant number of passengers on long haul flights do use the toilet and this level of usage would justify surveillance efforts.
Wastewater testing at all stages of the trip?
The question is whether wastewater testing could be undertaken at multiple stages of a long-haul flight to create a cumulative risk assessment of passengers from a specified origin? This could mean collecting data from the airport pre-departure terminal, during the flight, and upon arrival at the destination. Clearly, data sets would be more problematic at the pre-departure terminal and the arrival terminal, however - the question is whether this testing still be significant when overlaid with the data from the flight itself?
Arguably, positive results at pre-departure could inform the risk profile of the origin destination even if it did not specifically indicate inbound passengers could be categorically associated with the possible risk. Positive tests upon arrival could narrow down the probabilities, and if overlaid with flight testing - could either corroborate and/or add to the overall sample size.
The degree to which the passengers from an origin could be guided into using facilities associated with specific flights, and then upon arrival at the destination - could have a major bearing on how useful data collected pre and after the flight could be.
Summary
As Amoruso and Baldovin (2021) note: 'the time has come for a revolutionary approach to be implemented and it urgently needs the joint efforts of the international community. Pandemics can be restrained to a certain extent, but ultimately the early identification of pathogens is our ace in the hole'.
Australia and New Zealand have the opportunity to take advantage of long international travel distances and emergent technology to detect future pandemics early.
This could be through the deployment of wastewater testing at single or multiple points along air travel passenger journeys. This non-intrusive surveillance could allow emerging pandemics to be detected before passengers arrive within the bounds of a national jurisdiction (i.e. pre-departure, during the journey, and upon arrival but pre-border).
This early detection could allow Australia and New Zealand to reduce the likelihood of a pandemic entering its jurisdiction, provide vital near real time intelligence to determine risk levels, and help with ongoing monitoring and management of a pandemic.
While the technology to undertake such surveillance already exists, it is clear more research would be helpful around a few aspects of this proposition relating to:
Airport terminal facilities design and layout and the extent this could help current and future wastewater testing;
Waste water testing technology and the extent innovations around Internet of Things (IoT) and other emergent areas could assist the early detection of pandemics;
Legal, regulatory, and jurisdictional aspects and the necessity for international cooperation and co-ordination;
The possible impacts upon the aviation industry, airport, airlines, and international movement of travellers more generally;
The political will and leadership required to undertake such innovative approaches;
The connection and interdependence between a domestic and/or international jurisdictional pandemic response framework and infrastructure for such new technology.
Despite these questions, the potential benefits of undertaking wastewater testing at single or multiple points in the travellers journey arguably merit further investigation and investment.
The bigger question is whether Australia and New Zealand (or any country) can afford NOT to make such an investment?
References:
Ahmed W, Bivins A, Simpson SL, et al. Wastewater surveillance demonstrates high predictive value for COVID-19 infection on board repatriation flights to Australia. Environ Int 2022;158:106938. https://doi.org/10.1016/j.envint.2021.106938 PMID:34735954
Amoruso I, Baldovin T. On-board toilets of long-haul flights: is sewage epidemiology effective for COVID-19 global surveillance? Travel Med Infect Dis. 2021 Mar-Apr;40:102006. doi: 10.1016/j.tmaid.2021.102006. Epub 2021 Feb 26.
Farkas K, Williams R, Alex-Sanders N, Grimsley JMS, Pântea I, Wade MJ, et al. (2023) Wastewater-based monitoring of SARS-CoV-2 at UK airports and its potential role in international public health surveillance. PLOS Glob Public Health 3(1): e0001346. https://doi.org/10.1371/journal.pgph.0001346
Hjelmsø M.H., Mollerup S., Jensen R.H., Pietroni C., Lukjancenko O., Schultz A.C., Aarestrup F.M., Hansen A.J. Metagenomic analysis of viruses in toilet waste from long distance flights - a new procedure for global infectious disease surveillance. PloS One. 2019;14 doi: 10.1371/journal.pone.0210368.
IATA - Air Connectivity (iata.org) - impacts on trade and economy
Kamalrathne T, Amaratunga D, Haigh R, Kodituwakku L. Need for effective detection and early warnings for epidemic and pandemic preparedness planning in the context of multi-hazards: Lessons from the COVID-19 pandemic. Int J Disaster Risk Reduct. 2023 Jun 15;92:103724. doi: 10.1016/j.ijdrr.2023.103724. Epub 2023 Apr 29. PMID: 37197332; PMCID: PMC10148710.
Morfino RC, Bart SM, Franklin A, et al. Notes from the Field: Aircraft Wastewater Surveillance for Early Detection of SARS-CoV-2 Variants — John F. Kennedy International Airport, New York City, August–September 2022. MMWR Morb Mortal Wkly Rep 2023;72:210–211. DOI: http://dx.doi.org/10.15585/mmwr.mm7208a3.
Nieuwborg, Alexander; Melles, Marijke; Hiemstra van-Mastrigt, Suzanne; Santema, Sicco (2024) How can airports prepare for future public health disruptions? Experiences and lessons learned during the COVID-19 pandemic from a systemic perspective based on expert interviews. Transportation research interdisciplinary perspectives, January 2024. Vol 23
Peccia, J. et al. Measurement of SARS-CoV-2 RNA in wastewater tracks community infection dynamics. Nat. Biotechnol. 38, 1164–1167 (2020).
World Trade Organisation (WTO) - wts2020chapter03_e.pdf (wto.org)
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