COVID-19 in New Zealand and the impact of the national response: a descriptive epidemiological study

Abstract

BackgroundIn early 2020, during the COVID-19 pandemic, New Zealand implemented graduated, risk-informed national COVID-19 suppression measures aimed at disease elimination. We investigated their impacts on the epidemiology of the first wave of COVID-19 in the country and response performance measures. MethodsWe did a descriptive epidemiological study of all laboratory-confirmed and probable cases of COVID-19 and all patients tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in New Zealand from Feb 2 to May 13, 2020, after which time community transmission ceased. We extracted data from the national notifiable diseases database and the national SARS-CoV-2 test results repository. Demographic features and disease outcomes, transmission patterns (source of infection, outbreaks, household transmission), time-to-event intervals, and testing coverage were described over five phases of the response, capturing different levels of non-pharmaceutical interventions. Risk factors for severe outcomes (hospitalisation or death) were examined with multivariable logistic regression and time-to-event intervals were analysed by fitting parametric distributions using maximum likelihood estimation. Findings 1503 cases were detected over the study period, including 95 (6•3%) hospital admissions and 22 (1•5%) COVID-19 deaths. The estimated case infection rate per million people per day peaked at 8•5 (95% CI 7•6-9•4) during the 10-day period of rapid response escalation, declining to 3•2 (2•8-3•7) in the start of lockdown and progressively thereafter. 1034 (69%) cases were imported or import related, tending to be younger adults, of European ethnicity, and of higher socioeconomic status. 702 (47%) cases were linked to 34 outbreaks. Severe outcomes were associated with locally acquired infection (crude odds ratio [OR] 2•32 [95% CI 1•40-3•82] compared with imported), older age (adjusted OR ranging from 2•72 [1•40-5•30] for 50-64 year olds to 8•25 [2•59-26•31] for people aged ≥80 years compared with 20-34 year olds), aged residential care residency (adjusted OR 3•86 [1•59-9•35]), and Pacific peoples (adjusted OR 2•76 [1•14-6•68]) and Asian (2•15 [1•10-4•20]) ethnicities relative to European or other. Times from illness onset to notification and isolation progressively decreased and testing increased over the study period, with few disparities and increasing coverage of females, Māori, Pacific peoples, and lower socioeconomic groups.Interpretation New Zealand's response resulted in low relative burden of disease, low levels of population disease disparities, and the initial achievement of COVID-19 elimination.

Impact of the COVID-19 nonpharmaceutical interventions on influenza and other respiratory viral infections in New Zealand

“…These included (1) blocking importation of the virus (border closure to non-New Zealanders and 14-day quarantine for returning travellers); (2) stamping out transmission within NZ (widespread testing, isolating cases, contact tracing and quarantine of exposed persons); (3) physical distancing measures (stay-at-home orders, cancelling all gatherings, closing schools, non-essential businesses and all public venues and restricting domestic travel); (4) individual infection prevention and control measures (promoting hand hygiene and cough etiquette, staying home with mild respiratory symptoms and mask wearing if unwell); and (5) communicating risk to the public and various stakeholders. The implementation of these NPIs combined with public compliance effectively eliminated community transmission of COVID-19 during the first wave (12 February to 13 May 2020), achieving 101 consecutive days without detection of community COVID-19 cases 2 , 3 . Since this implementation, NZ has continued to apply NPIs in various forms up until submission of this report 1 .…”

Lessons From the First Wave of COVID-19: Work-Related Consequences, Clinical Knowledge, Emotional Distress, and Safety-Conscious Behavior in Healthcare Workers in Switzerland

“…Several studies have recently examined the responses to the COVID-19 pandemic in different countries. They adopted different perspectives, analyzing the effectiveness of governmental policies ( Dergiades et al, 2020 ; Desson et al, 2020 ), epidemiological responses ( Jefferies et al, 2020 ), testing, contact tracing and isolation ( Salathe et al, 2020 ), lockdown policy ( Faber et al, 2020 ), preparation of the healthcare sector ( Barro et al, 2020 ), as well as key learned lessons ( Han et al, 2020 ). However, empirical studies of how such measures are perceived by the healthcare staff, and of how the pandemic has affected their work situation from their own perspective, are still scarce.…”

Too Tight or Too Loose? The stringency of Mobility Restriction Policy Response by the Government of Sri Lanka against Covid-19

“…Subsequently, with dropping case numbers, New Zealanders were able to downscale the measures. This could be one contributor of New Zealand's success in curtailing the Covid-19 pandemic so far (Jefferies et al 2020).…”