Category: ESR

Source: ESR

The Institute of Environmental Science and Research (ESR) meningococcal data for 2023 was released this week, indicating an overall reduction in the number meningococcal cases compared to 2022, from 72 in 2022 to 59 cases in 2023.

This change has been driven by a decrease in the number of cases among children under five years. In infants aged younger than one, case numbers declined from 22 to seven cases. There was also a reduction among children aged one to four years, from 15 to eight cases.

There was an increase in cases among those in the 15-24 age group, from 13 to 18 cases.

Because of the decrease in the number of cases under five, people aged 15-24 years make up an increased proportion of meningococcal cases – 30% in 2023 compared with 18% in 2022.

Overall, cases among Māori reduced from 34 cases in 2022 to 18 cases in 2023. 

Annual case numbers continue to be lower than they were prior to the COVID-19 pandemic when they reached a high of 139 cases in 2019.  

With low numbers, caution must be exercised in interpreting changes from year to year across any demographic group.

ESR notes that while case numbers continue to be lower than they were prior to 2020, meningococcal  disease remains a serious concern in New Zealand.  It is important to continue monitoring trends in order to inform policy decisions, including immunisation policy.

ESR meningococcal data are updated monthly on the ESR website – both in a monthly report and in a dashboard.

The ESR meningococcal dashboard can be found here(external link).

Source: ESR

Everything we do at ESR is driven by our mission to detect, connect and protect – so we can deliver cutting-edge science that benefits all Aotearoa New Zealand, from our bustling urban centres to most isolated rural environments. I’m delighted to reflect on the difference our science has made for New Zealand over the past year, and to share some highlights with you. 

We saw our mission in action throughout 2023, with the ongoing detection and measuring of COVID-19(external link) in our communities. As self-reporting has decreased, ESR’s wastewater testing, alongside our genomics surveillance, has proved vital for establishing levels of the virus, to support health providers and the public with their decision making. 

To further support decision making, this year our public health surveillance information shifted to live in one place as part of a new look Ngā Kete Intelligence Hub(external link). Having all our public health intelligence in a centralised hub is a huge step forward for making this information accessible. Stay tuned for more updates to our website in the new year, as we continue to improve how we present our research and services, to have an even greater impact for our communities. 

On the influenza front, 2023 marked five years since the WellKiwis programme launched(external link). The programme is playing a key role in helping ESR experts better understand immunity and how more effective vaccines could be developed for influenza and other viruses. 

ESR continues to lead the way when it comes to embracing new technologies. ESR’s experts turned their attention to how artificial intelligence could further enhance research, while ensuring AI’s power is harnessed in an ethical, productive way. To help guide use of AI, we’re proud to have signed-up to the Algorithm Charter for Aotearoa New Zealand(external link), which commits to ensuring New Zealanders have confidence in how government agencies use data and algorithms. 

We were also excited to host the ESR Symposium on Precision Health, bringing together people from a range of sectors to help understand the opportunities for New Zealand in this rapidly advancing field of data-informed healthcare. 

We’re extremely proud of the work undertaken with our co-host, the University of Otago, and key Māori partners, to grow and embed Te Niwha, a holistic approach to reduce inequities in infectious diseases and health responses(external link). With a commitment to the principles of Vision Mātauranga,Te Niwha provides a comprehensive approach to infectious disease research and response in Aotearoa New Zealand, focusing on partnership and collaboration with Māori and our most vulnerable communities. 

ESR has championed increased CRI collaboration through pan-Crown research institution initiatives such as improving Māori data sovereignty practices and developing a Pacific environmental exposure assessment to investigate and assess potential climate change risks. 

As an example of ESR collaboration, we’re leading a New Zealand Government Jobs for Nature project gathering freshwater data to model potential health risks from swimming. Nine councils are involved in collecting samples from 40 water bodies to create a new model that will support New Zealand’s freshwater recreational guidelines(external link). ESR scientists also worked alongside GNS and Environment Canterbury on an online tool for microbial risk assessment of land use on drinking water supplies(external link). The tool is designed to give guidance to councils and others seeking to protect the safety of their drinking water sources. 

We continue to push the boundaries in science excellence, including building on the commercial successes of ESR’s ground-breaking and award-winning products Lumi™ and STRmix™(external link). Lumi is now being used as a frontline policing tool by the New Zealand Police for drug detection. Lumi’s success in being awarded the Excellence in Forensic Science Award at the World Police Summit in 2023, is testament to the innovation of ESR’s scientists working in collaboration with the New Zealand Police. 

This really is just a snapshot of the important science undertaken by ESR this year. These achievements have only been made possible through the dedicated work of our incredible colleagues and partners. I am so proud of the dedication, spirit and professionalism of all our people, who continue to deliver outstanding contributions to the health and wellbeing of our communities. The ESR team looks forward to our continued collaborations throughout 2024. 

Source: ESR

‘The team was the key ingredient that made Lumi™ happen’ – Dion Sheppard, Lumi™ Drug Scan Team Awardee

Trust and confidence at the frontline stems from reliable and consistent decision making. Lumi™ Drug Scan, developed by a team of ESR forensic experts working with police, is a revolutionary approach to drug investigations, making forensic science accessible to frontline responders. Lumi™ enables police to safely detect illicit drugs within seconds, while providing rich data and insights about drug use in Aotearoa.

“Lumi™ can currently detect methamphetamine, cocaine, and MDMA, which are the three highest priority targets for New Zealand Police. They’re the drugs that represent the highest harm. It started in conversations with Police about what they were wanting to do.

“The team was really the key ingredient that made Lumi™ happen – we were lucky enough to have a really good diversity of expertise to draw on,” says Dion Sheppard, Lumi™ Drug Scan Manager.

This Kiwi technology delivers science at the point of need, empowering rapid detection of illicit substances by analysing packaged samples on a palm-sized scanning device that harnesses infrared to determine if cocaine, ecstasy, or methamphetamine are present. The device is paired via Bluetooth with the Lumi™ App on the officer’s smartphone, powered by sophisticated machine learning algorithms in the cloud developed from over 600,000 scans from drug samples curated by ESR scientists. Lumi™ is a game-changing innovation supporting better policing and drug harm reduction in communities.

“A key enabler of the Lumi™ project was that relationship with New Zealand Police,” Dion says.

“Congratulations for winning the Team Award. It’s a fantastic recognition of all the hard work and collaboration between New Zealand Police and ESR,” says Inspector Simon Welsh, Manager Implementation & Evaluation, Evidence Based Policing Centre. 

“Lumi has certainly got an amazing response from our frontline staff. It makes it easier to identify drugs on the side of the road, and it’s more efficient.”

Source: ESR

Renowned physicist and data science expert, Professor Frank Krauss, to deliver talk on innovative use of data to tackle world’s most urgent challenges – from disease outbreaks to climate change

 During the COVID-19 pandemic, Krauss developed the internationally renowned JUNE model, enabling human behaviour to be factored into simulations with increasing sophistication. This model was used by the World Health Organization and the United Nations to guide decision-making in contexts such as refugee camps.

Now, he is exploring the next generation of data and simulation approaches that are transforming how we can envisage and prepare for emerging threats – with applications from disease outbreaks to the impacts of climate change.

Krauss’s visit is hosted in New Zealand by the Institute of Environmental Science and Research (ESR) through the Vision Awards, to build on the lessons from COVID-19 to ensure New Zealand has the science and surveillance capability it needs.

The seminar, co-hosted by ESR and Victoria University of Wellington, will highlight the critical role of collaboration when tackling complex problems and realising the full potential of data-driven solutions.

As a Professor in the Department of Physics and the Centre for Particle Theory, Professor Krauss’s interdisciplinary approach has made him a leading figure in both physics and data science.

What sets Professor Krauss’s work apart is its real-world impact. The open-source JUNE model garnered attention for its potential to be applied internationally, aiding governments and health organizations in their efforts to combat the pandemic. Intrigued by the dynamics of epidemics, Krauss’s model not only aids in understanding the spread of the virus but also offers insights for strategic interventions. Its adaptation for refugee camps showcased the model’s versatility and its potential to address health challenges in diverse settings.

ESR Chief Data and Analytics Officer Jan Sheppard says Krauss’s insights are valuable as New Zealand builds its capability in using the power of data and highly advanced simulation tools to make a step change in our approach to health surveillance.

“No doubt COVID-19 spurred incredible work in data modelling and scenario planning, and we saw the effectiveness of this in New Zealand. But since then, the technology and tools have advanced enormously, powered by AI and phenomenal data sets. Professor Krauss’s insights are not about our last pandemic, but our next one.”

Event Details:

Title: Data, Models and Reality
Date and Time: Thursday 7 December, 4PM-5:30PM
Location: Government Building Lecture Theatre, Pipitea campus GBLT1, Victoria University

About Professor Frank Krauss

Professor Frank Krauss is a renowned academic currently serving as the Director of the Institute for Data Science at Durham University, and a Professor in the Department of Physics and the Centre for Particle Theory. His academic journey began with undergraduate studies at TH Darmstadt, followed by a PhD at TU Dresden, and several postdoctoral positions. His research focuses on the phenomenology of particle physics, a branch of theoretical physics that bridges the gap between abstract models for the fundamental interaction of matter and experimental phenomena. He has made significant contributions to the field, including the development of the SHERPA Monte Carlo event generator, a simulation tool that describes experimental reality in great detail. Professor Krauss has also been involved in the development of JUNE, an open-source framework for the detailed simulation of epidemics based on social interactions in a virtual population.

Source: ESR

Tackling drug resistance: global crisis requiring local action 

To mark World AMR Awareness Week (18-24 November) ESR clinical microbiologist Dr Juliet Elvy explores Aotearoa’s place in the global landscape of drug resistance, and the role of ESR’s Antibiotic Reference Laboratory in controlling resistant infections. 

Amid countless global challenges, there’s one silently lurking crisis that is threatening the very core of modern medicine – Antimicrobial Resistance (AMR). Referred to by the World Health Organisation (WHO) as one of the top ten global threats facing humanity, AMR poses a grave danger. It’s a phenomenon where microorganisms, often dubbed ‘superbugs’, have developed resistance to most antimicrobials, rendering them ineffective. The root cause? The overuse and misuse of antibiotics.  

The urgency of addressing AMR is akin to the climate crisis, a ticking time bomb. Without effective antimicrobials, routine medical procedures, from surgery to cancer chemotherapy and organ transplantation come with heightened risks due to surgical site infections. However, AMR is not limited to a single sector; it affects humans, animals, plants, food, and the environment, necessitating a unified, multi-sectorial approach, often referred to as the ‘One Health’ approach. 

Hence why the theme for this year’s World AMR Awareness Week (WAAW) is ‘Preventing Antimicrobial Resistance Together’. This global campaign, led by WHO from November 18 to 24, strives to raise awareness about antimicrobial resistance and promote best practices to prevent the spread and development of drug-resistant infections. Emphasizing the fight against resistance, the campaign’s mantra, ‘Antimicrobials: handle with care’, underscores the importance of responsible use.  

In Aotearoa New Zealand, the Institute of Environmental Science and Research (ESR) plays a pivotal role in detecting resistant infections. ESR’s Antibiotic Reference Laboratory provides national surveillance of antimicrobial resistance among human pathogens and the typing of pathogens causing outbreaks. Clinical microbiologists collaborate with ESR’s Antibiotic Reference Laboratory to identify rare and emerging resistant bacteria. Routine monitoring allows us to stay one step ahead of outbreaks, detecting resistant infections, identifying transmission patterns and preventing their spread before it’s too late. ESR aligns its efforts with the WHO’s list of priority pathogens, ensuring the most effective tracking and surveillance.  

Drug resistance knows no borders 

As New Zealand grapples with the AMR crisis, it’s essential to assess our standing. The nation’s use of antibiotics is relatively high on a global scale, comparable to some of the top antibiotic-consuming countries. Surprisingly, our resistance levels remain relatively low. Our small population density and geographical isolation may be contributing factors.  

However, this isn’t something we can take for granted. A recent Vancomycin-resistant Enterococci (VRE) outbreak   in Waikato hospital serves as a wake-up call and stark reminder that we cannot afford complacency. Enterococci are bacteria found in human intestines and the genital tract and can cause infections. While VRE, a bacterium resistant to many antibiotics, is not yet endemic in New Zealand, it is crucial to acknowledge the potential threat and take urgent action.  

Addressing resistant infections 

So, what can we do as a nation to ensure our antimicrobial resistance levels remain low? Ensuring we implement robust surveillance of AMR and antimicrobial usage and have adequate resources to adhere to infection prevention measures, is critical. The COVID-19 pandemic caused a decrease in AMR surveillance data, primarily due to the strain on laboratory resources. Additionally, New Zealand currently lacks ongoing antimicrobial usage reporting, a surveillance tool that is essential for the country to implement.  

Aside from a nationwide effort, there are steps we can take as individuals to prevent the spread of resistant infections. Not using antimicrobials when they are not needed and following the basic principles of infectious disease prevention is crucial to prevent outbreaks, and AMR is no different. Making sure we are up to date on vaccinations is also paramount, as it not only protects against known pathogens but also contributes to overall community immunity. Additionally, we must be vigilant when travelling to high-risk countries, as these pathogens know no borders. Maintaining personal health practices goes hand in hand with the broader efforts to combat AMR. 

In the face of the AMR crisis, New Zealand has a unique opportunity to lead the way with responsible antimicrobial usage and surveillance. It is crucial that as a nation, we collectively recognise the gravity of this issue and take proactive steps to ensure a future where our healthcare system remains effective. By adhering to basic principles of antimicrobial stewardship, infectious disease prevention and implementing consistent infection control practices, we can navigate the path towards a future where AMR poses a significantly lower risk.  

Source: ESR

There’s nothing like the start of the barbecue season to bring to mind E. coli.  

But when ESR microbiologist Jackie Wright made the first case report of Escherichia coli O157:H7 in Aotearoa New Zealand in 1993 – along with collaborators Dianne Fraser and Michael Baker – she wasn’t aware just how much she was making history. 

This year ESR is celebrating the thirtieth anniversary of the discovery of Shiga-toxin producing E. coli (STEC) in Aotearoa, and Jackie’s contribution to public health and food safety. 

E coli O157:H7 causes illness in humans by producing powerful Shiga toxin, which can damage the intestinal lining. The E. coli strains that make Shiga toxin are also called Shiga toxin-producing E. coli, or STEC. STEC infection is a significant foodborne disease, and in 2022, the number of cases reported in New Zealand trumped other well-known diseases like salmonellosis and listeriosis.

In her recent seminar presentation “Clinical STEC in Aotearoa New Zealand,” Jackie says that she chose to include E. coli O157:H7 in the research survey “at the last minute,” because of the recent Jack in the Box outbreak caused by this bacterium, which was linked to undercooked mince patties sold by the fast-food chain in the United States.  

Professor Michael Baker, epidemiologist and public health physician at the University of Otago, says of the discovery: “Recognising the presence of E. coli O157 for the first time in Aotearoa New Zealand was a major milestone for enteric disease surveillance in this country. This discovery was a tribute to Jackie’s initiative and high level of laboratory expertise.” 

Jackie herself is more self-effacing about the discovery, saying: “We all know in microbiology, if you look, you find. This isn’t a case of being in the right place when STEC O157 just happened to appear, if someone had looked before, they would have found it.”  

Nevertheless, after this first discovery of STEC O157 in Aotearoa New Zealand, more people started looking for it, which set the wheels in motion for the robust national STEC surveillance we now have. “In the subsequent 30 years, this pathogen has emerged as an important cause of severe enteric infection across the globe. It is also a hazard that requires close control by our meat export sector,” says Michael.  

Jackie herself has remained a constant in this space over the last three decades. While she left ESR in the late 1990s, she continued to work on enteric pathogen detection in the commercial food sector and then moved into human diagnostic microbiology. Then Jackie worked for 12 years in a small community laboratory, before returning to ESR in 2017 to lead the Enteric Reference Laboratory team.  

The STEC surveillance data analysed by ESR’s Enteric Reference Laboratory team is essential to understanding the epidemiology of the pathogen including prevalence, circulating strains, and disease severity. The work is also critical to identifying and investigating outbreaks.  

On the legacy of Jackie’s discovery, Michael says: “Jackie should be very proud of her lasting contribution to protecting public health in Aotearoa New Zealand. It was a pleasure to work with her during my time at ESR.” 

And for all of us, we can appreciate having a better understanding of food safety during this upcoming season of picnics and potlucks.  

Source: ESR

This year’s NIWA Wellington Regional Science & Technology Fair kept Michelle Christensen and Yasmin Liu from ESR’s Forensic Business Group extra busy, as they decided which aspiring local scientists would receive the coveted ESR Prize.

ESR is delighted to have been associated with the Science Fair since it began in the 1990s, with the ESR Prize having ignited scientific passion among countless local school students. This year marked the first since 2019 in which the Science Fair was able to occur without COVID-19 restrictions, a stark contrast to the online only fairs of 2020 and 2021. The Science Fair was able to return to the Hub at Victoria University’s Kelburn Campus, with all exhibits together again in the one large space.

“It was great to see all the exhibits back together, so you can appreciate just how much incredible innovation and imagination there is among contestants,” says Michelle, Senior Scientist and Forensic Toxicologist.

Fellow judge and Senior Scientist Yasmin agrees.

“We were proud to represent ESR. It was amazing how many of the students know what value ESR brings to New Zealand communities, and the awesome careers they could potentially have here one day as scientists.”

2023 ESR Prizes were awarded to:
•    Isabelle Aduna (Wellington Girls College): Riding the Waves
•    Elodie Dent (Muritai School): How drinkable is our water?
•    Maggie Dinniss (St Mark’s Church School): It runs in the family or does it?                
•    Anais Mancencal Sellier (Seatoun School): Your Tiny Body Guards 
•    Meenakshi Ramaswamy (St Oran’s College): for The Ink Case.

So what advice do Michelle and Yasmin give to children and young people interested in science and technology?

“Follow your passion and don’t think ‘I can’t’,” says Michelle. “If you have a flair for cooking or like observing rocks while tramping, you already are ‘doing’ science. Talk to your whānau and teachers about your interests so they can help you grow.”

Science literally runs in the blood for Michelle and her family – they are after all keen participants in the revolutionary ESR WellKiwis study(external link) led from right here in Wellington, which is contributing to global understanding about immunology and how viruses spread.

“The world needs more scientists,” says Yasmin. “It’s awesome to see how many there will be in Wellington in a few years, judging by the popularity of this year’s NIWA Science Fair!”

“We’re looking forward to seeing a whole lot more amazing ideas at next year’s Science Fair,” says Michelle.

You can find out more about the NIWA Wellington Regional Science & Technology Fair here(external link). 

Source: ESR

ESR’s Lumi™ Drug Scan has been shortlisted for a prestigious KiwiNet Research Commercialisation Impact Award.

The shortlisting comes hot off the heels of Lumi™ winning the Excellence in Forensic Science Award(external link) at the 2023 World Police Summit in March, and is further validation of the difference this game-changing illicit drug detection service is making to communities.

Lumi™ brings together the power of a lightweight device that can scan for traces of cocaine, MDMA and methamphetamine using infrared lights, giving instantaneous results via Bluetooth to the powerful Lumi™ mobile app. These insights are also available in the sophisticated Lumi™ dashboard, which charts regional drug trends.

With 18 finalists in total, the 2023 KiwiNet Awards will be announced in Auckland on 28 September. The other finalists in the MAS Commercialisation Impact Award category are:

• TDRIand Lincoln Agritech: Reducing roading costs with rapid subsurface moisture detection
• XFrame and Wellington UniVentures: Reusable framing for the next generation of sustainable construction.

You can find out more on KiwiNet’s website(external link).

Lumi™ has been co-developed by New Zealand Police.

The Ministry of Business, Innovation, and Employment’s Strategic Science Investment Fund (SSIF) has provided invaluable funding to this project. SSIF enables the prioritisation and purchase of science in areas that ensure the long-term stability and impact of the science system.

Source: ESR

St. Jude Children’s Research Hospital scientists, in collaboration with the Institute of Environmental Science and Research (ESR) Limited, found that immune cells present in people months before influenza (flu) infection could more accurately predict if an individual would develop symptoms than current methods which primarily rely on antibody levels. The study found certain immune cells were associated with increased protection, while other immune cells were associated with increased susceptibility to developing symptoms after catching the virus. The findings have implications for new approaches to public health and were published today in Nature Immunology. 

“We’ve been struggling for decades, if not centuries, with why some people get sick with infections and some don’t,” says co-corresponding author Richard Webby(external link), Ph.D., St. Jude Department of Host-Microbe Interactions(external link). “This is one of the best attempts to try and figure that out for influenza. We were able to measure many different immune parameters from a single blood draw and correlate them with protection from, or susceptibility to, infection symptoms.”

Functional diversity improves anti-influenza immune performance

The researchers found that having a more functionally diverse set of immune cells was correlated with increased protection from flu symptoms. The group identified these cells by comparing the immune cells present in the blood of patients who had symptoms from flu infection to those who were asymptomatic or uninfected. The blood samples, taken up to six months before that flu season, showed very different sets of immune cells in the two groups. Those without symptoms not only had a more functionally diverse set of immune cells but those cells were also associated with an influenza-specific long-term response, sometimes called the memory response. Patients with symptoms tended to have a more similar set of inflammatory immune cells, which are more likely to be involved in a nonspecific, functionally narrow and short-term response.

The analysis included volunteers in the surveillance for a community cohort-based influenza-like illness (SHIVERS-II) study in New Zealand. SHIVERS-II includes a unique cohort of volunteer patients that the study tracks over time, including their health information. For this study, the volunteers regularly had their blood drawn so the scientists could characterize their immune cells and find which were associated with protection from flu symptoms. 

“The SHIVERS platform, which represents a long-running collaboration between St. Jude and ESR, has been tremendously successful because of the willingness of participants to stay engaged in the study,” sasy co-corresponding author Sue Huang, Ph.D., principal investigator for SHIVERS-II and the World Health Organization National Influenza Centre director at ESR. “It is great to see their efforts coming to fruition.”

“Our results show that the balance of different immune cells in people can be extremely biased,” says senior and co-corresponding author Paul Thomas(external link), Ph.D., St. Jude Department of Immunology(external link). “You might build up an immune cell army that is exceptional at fighting off one kind of infection, but then that can make you feel sicker from another kind of infection. By understanding which immune cells are the best for fighting the flu, we can start designing vaccines to push for those populations that are most protective.” 

“The baseline immune state before vaccination is known to significantly vary across age, sex, vaccination status, infection history and more,” says co-first author Aisha Souquette, Ph.D., St. Jude Department of Immunology. “By understanding the different types of immune profiles that can provide protective responses, we can tailor and optimize our vaccine platforms for populations with distinct baseline immune states.”

For developing future tailored approaches, pushing for a particular type of cell or particular immune proteins, such as antibodies, is less important than evaluating the collective contributions of all the immune cells, which may be easier than current methods. 

“We observed that the protective, or susceptibility, cell profile’s makeup is less important than the overall, often converging, function,” says co-first author Robert Mettelman, Ph.D., St. Jude Department of Immunology. “This means that we can more broadly evaluate protection or susceptibility at the level of a cell profile, making it easier to evaluate across studies.” 

Indeed, this study showed that those vaccinated for the flu generally had increased protective anti-flu immune cells, improving their chance of avoiding symptoms. Those rarer individuals who were unvaccinated and avoided symptoms seemed to have a set of immune cells that mimicked the functions of the protective cells in the vaccinated population. This may explain why some people are less affected by the flu, even when unvaccinated, than others, but it still suggests vaccination creates the best chance of avoiding symptoms. One way to encourage this vaccine uptake is to determine the inherent risk in staying unvaccinated accurately. 

Source: ESR

UC researchers and collaborators create world-first statistical model with potential to better inform public health responses to infectious diseases.

A team of researchers, including Te Whare Wānanga o Waitaha | University of Canterbury (UC) Dr Leighton Watson(external link) and Professor Michael Plank(external link), combined wastewater data with reported case numbers to create a statistical model that could be used to inform public health responses to infectious diseases worldwide.

Their study is based on data from the Institute of Environmental Science and Research (ESR)(external link) wastewater COVID-19 surveillance programme and Covid-19 data collected in Aotearoa New Zealand.

The disease surveillance tool analyses data in a way no other study has previously done – combining wastewater data and reported case numbers to estimate how the case ascertainment rate, or proportion of infections reported, has changed over time. The model also estimates the effective reproduction number.

School of Mathematics and Statistics Lecturer Leighton Watson(external link)’s model provides a clearer picture of the state of an epidemic, disease dynamics and infections in the community.

“While the results are not the only piece to the puzzle, the model could be used as an additional source of information to inform public health policy decisions and hospital capacity planning,” Watson says.

He explains the model could be used by any country where most people are connected to the wastewater system. The model could be applied nationally or regionally and help inform planning of public health responses to multiple infectious diseases.

Watson noted that over time government restrictions and testing guidelines have been eased. “At first, people would test every time they got a sore throat. Anecdotally, now it seems like many people are assuming they are just under the weather because, for example, their kids bring every single bug possible home from school.”

Watson says fewer cases could mean fewer infections or fewer people reporting. Reported cases during the second wave in July 2022 were significantly lower than in the first wave in February and March 2022. However, the model suggests that there was a substantial drop in case ascertainment between the waves and that true numbers of infections were actually similar.

Wastewater surveillance has proven to provide valuable data on COVID-19 trends in the community in New Zealand and overseas. This led the research team to investigate how clinical and wastewater data could be combined to provide a better overall picture of the pandemic.

“People infected with SARS-CoV-2, which causes COVID-19, generally shed it in their stools, whether they have symptoms or not. If they flush their stool using a toilet connected to the wastewater network,  genetic material of the virus (RNA) can be detected in the wastewater collected at the local wastewater treatment plant” says Dr Joanne Hewitt, who leads the COVID-19 in wastewater surveillance work at ESR.

“By sampling wastewater, we can pick the virus up independent of whether people are testing or not, allowing a much wider cross-section of the community to be included,” says Hewitt. SARS-CoV-2 viral levels in New Zealand wastewater, alongside reported cases, can be viewed on a public dashboard(external link).

“Everyone who lives somewhere that’s linked up to the town wastewater system is going to shed the virus into the wastewater if they have Covid. If they are plumbed into the wastewater system and we are sampling it, we can pick that up independent of whether people are testing or not” Watson says.

According to the researchers the model provides the most accurate source of data on case ascertainment rate and effective reproduction numbers currently available.

Watson and Professor Plank worked alongside research colleagues from ESR(external link) and the University of Oxford’s Department of Statistics(external link) for the study. Their research, Improving estimates of epidemiological quantities by combining reported cases with wastewater data: a statistical framework with applications to COVID-19 in Aotearoa New Zealand(external link), was funded by New Zealand’s Ministry of Health(external link), the Public Health Agency(external link) and the Department of Prime Minister and Cabinet(external link).