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COVID-19 research team earns Liley Medal for landmark study on NZ’s pandemic response

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Dr Sarah Jefferies (fourth from left) and team

Public health expert Dr Sarah Jefferies and team have been awarded the Health Research Council’s prestigious Liley Medal as part of the Royal Society Te Apārangi’s Research Honours for their landmark paper analysing the impact of New Zealand’s response to the COVID-19 pandemic.

Lead author Dr Jefferies (pictured fourth from left), who specialises in communicable disease surveillance and responses to outbreaks at the Institute of Environmental Science and Research (ESR) in Wellington, worked with a multi-agency team on the highly cited Lancet Public Health1 paper during the nationwide public health response to the first wave of COVID-19 in New Zealand.

The team included experts from ESR, the Ministry of Health, Massey and Otago universities, and data analytics company Epi-interactive. They carried out an epidemiological study of all laboratory-confirmed and probable cases of COVID-19, and all patients who were tested for the SARS-CoV-2 virus that causes COVID-19, in New Zealand from 2 February to 13 May 2020, after which time community transmission of the virus initially ceased.

This world-leading paper assessed the impacts of national non-pharmaceutical interventions such as border closures, physical distancing and lockdowns on the distribution, transmission patterns and severity of COVID-19 in the attainment of an explicit nationwide goal of COVID-19 elimination.

Dr Jefferies says before COVID-19 became a household name, some of the team were already heavily involved with helping coordinate the national response, including setting up the surveillance systems to detect the new disease, developing systems for new virus detection capabilities, and supporting public health units in their enormous efforts to detect, trace and control COVID-19, and collect the surveillance data that informs the response.

“When things settled down a little after the first wave, we began putting together the key research questions we needed to answer, such as what have the different public health interventions deployed meant for the burden of disease in New Zealand? There was a great opportunity to build on the analyses and reporting we were producing during the first wave,” says Dr Jefferies.

The study was divided into five phases, from the initial travel restriction to the 10-day rapid escalation of measures just before lockdown, the first and second half stages of lockdown, and the de-escalation to alert level 3 until 13 May 2020.

Dr Jefferies says they were especially concerned about whether certain population groups would be disproportionately affected by COVID-19 as had been the case overseas.

“Internationally, high-risk groups such as healthcare workers and Indigenous peoples were among the most severely affected by COVID-19. But in the first wave in New Zealand, we found that healthcare workers and Māori did not seem to be disproportionately affected.”

She says although the rapid control of community transmission through mandatory physical distancing gave New Zealand time to enhance the response and limit COVID-19 illness and deaths, inequities were still evident. Older people, aged residential care residents, people reporting at least one underlying health condition, and Asian and Pacific peoples were found to be at higher risk of severe illness from COVID-19 than other populations.

Our study highlighted the urgent and ongoing need for countries to address systemic barriers – such as healthcare access – to achieve equitable health outcomes for minority and higher-risk groups. Unfortunately, as we know, there have been further inequities in the burden of COVID-19 in New Zealand since that first wave,” says Dr Jefferies.

The team’s paper has received high international attention as an important scientific examination of New Zealand’s extraordinary initial pandemic response, scoring within the top 0.1 percent of all research outputs reviewed.2 Dr Jefferies says the findings have been especially relevant to other higher income countries and island nations.

“Before the widespread availability of the COVID-19 vaccine in early 2021, countries like Scotland adopted some of the more stringent non-pharmacological measures New Zealand had used, like a period of mandatory border quarantine to limit the importation and community spread of COVID-19.”

HRC Chief Executive Professor Sunny Collings says this study has contributed to New Zealand’s ongoing response to the COVID-19 pandemic and provided the international community with proof of how a stringent, evidence-informed nationwide public health response led to a low burden of COVID-19 relative to other countries and its initial elimination before the availability of an effective vaccine.

She says the fact that the team wrote this paper while at the same time providing real-time analysis and support to the Ministry of Health during the first wave of COVID-19 shows the scientific community’s resolve to pull together to support the huge demands of the pandemic.

“New Zealand’s relatively small health research workforce has worked tirelessly together with other health professionals to provide fast and accurate information to try to minimise the impact of COVID-19 on our communities. While the story of this pandemic is far from over, I believe we owe them all an enormous debt of gratitude,” says Professor Collings.

Dr Jefferies is continuing to work closely with the multi-agency team, including considering how they can produce rapid research outputs during the current delta variant outbreak.

“It remains nationally and globally important to understand the impacts of response measures and changing virus dynamics to inform our ongoing response and to prepare for future disease threats. As we open our borders, we will also be re-exposed to multiple infectious pathogens and preparing for this is going to be important, too,” says Dr Jefferies.

1 Jefferies, S. et al. COVID-19 in New Zealand and the impact of the national response: a descriptive epidemiological study. Lancet Public Health 2020; 5 (11): e612-23

2 Altmetric Attention Score, see

Photo caption: From left: Charlotte Gilkison, Julia Scott, Shevaun Paine, Sarah Jefferies, Virginia Hope, Patricia Priest, Nigel French, Andrea McNeill, Liang Yang. Not shown: Giles Graham, Namrata Prasad, Jonathan Marshall, Petra Muellner, Jillian Sherwood, Caroline McElnay.