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Winter Influenza Cases Down 99.9 Percent In New Zealand Due To COVID-19 Lockdowns


Jack Dunhill

Social Media Coordinator and Staff Writer

clockFeb 15 2021, 18:08 UTC
New Zealand Flag Mask

The authors suggest that whilst lockdowns lead to a decline in cases, human behavior also likely changed as a result of the pandemic. Image Credit: kovop58 /

Riding their impressive success in keeping COVID-19 cases low, New Zealand has also had a secondary success – they have reported almost no cases of influenza over the 2020 period. Likely a direct result of social distancing, lockdown, and wearing masks, preventative measures have resulted in a 99.9% reduction in flu cases, and may lead the way for reducing infectious disease prevalence in the future. 

The study, which was conducted by the Institute of Environmental Science and Research, Wellington, was published in Nature Communications


“Using multiple surveillance systems, we observed a parallel and unprecedented reduction of influenza and other respiratory viral infections in 2020.” state the authors. 

“This finding supports the use of these NPIs [nonpharmaceutical interventions] for controlling pandemic influenza and other severe respiratory viral threats.”  

New Zealand and its government has received overwhelming praise in recent months, with a response to the COVID-19 pandemic that has allowed most residents to enjoy group activities whilst other countries remain in strict lockdown. Despite receiving its first case of COVID-19 in February 2020, strict border control and regional lockdowns prevented case numbers from spiraling out of control.  

Now, in a comprehensive review of respiratory viral infections across NZ, it has been discovered that the country saw a huge decline in other diseases, particularly influenza. New Zealand has a regular seasonal increase in influenza cases, peaking in the winter months. However, 2020 saw a drastic reduction of 67.7% during lockdown and 99.9% after lockdown. Other respiratory viruses saw steep declines as well, including respiratory syncytial virus (98%), human metapneumovirus (92.2%), and rhinovirus (74.6%). 


The authors suggest that whilst lockdowns lead to a decline in cases, human behavior also likely changed as a result of the pandemic, and that may protect them from infectious disease. More people wash their hands, socially distance even when not in lockdown, and remain isolated when symptomatic than prior to COVID-19. 

It may call for a change in WHO guidelines in relation to influenza protective measures – which do not recommend NPIs currently – as they are thought to be impractical. The results here suggest that not only are they effective, but they also have significant applications in a range of other similar diseases as well. 

This is not the first example of COVID-19 measures having a knock-on impact across other diseases. A rare disease called acute flaccid myelitis, which spreads every two years and targets children, usually spikes during the summer but failed to reach close to the numbers seen during 2018 and 2016, with limited contact likely preventing it from spreading.  

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