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Auckland Hospital and Starship Childrens Hospital (Photo: Phil Walter/Getty Images)
Auckland Hospital and Starship Childrens Hospital (Photo: Phil Walter/Getty Images)

ScienceOctober 26, 2020

The lockdown stamped out a deadly virus. Its health impact did not stop there

Auckland Hospital and Starship Childrens Hospital (Photo: Phil Walter/Getty Images)
Auckland Hospital and Starship Childrens Hospital (Photo: Phil Walter/Getty Images)

In 2020, the Covid-19 pandemic prompted New Zealand and much of the world to undertake something few of us had ever contemplated: a near-total lockdown of society. In this Lockdown legacies series, James Dann explores the impacts of those extraordinary measures, intended and otherwise. Today: From traffic accidents and seasonal flu to heart disease, the indirect health effects of the Covid lockdown were many and varied.

This project was made possible thanks to support from the Aotearoa New Zealand Science Journalism Fund.

With most of the world deep in first or second waves of Covid-19, it doesn’t need to be said that the disease has had devastating effects on people’s health. While the lockdown was designed to break the chain, and minimise the spread of the disease, there were also other health effects from this period of forced isolation. In this article, I’ll be looking at some of the indirect health benefits of the Covid lockdown, from fewer traffic and workplace accidents, to a near eradication of the seasonal flu, and fewer presentations of heart disease. There may also be negative health impacts from the lockdown, with people not being able to see their GP in person, having to delay surgeries, and the impact of increased alcohol and drug consumption.


Much of the reduction in the number of deaths and injuries was a result of us staying home and not doing a hell of a lot. The road toll was just nine in April, a record low (over the last decade, there have been about 30 deaths a month; there were 45 in April of 2019). While many people were working from home, in some jobs this just isn’t possible, and many of these – construction, logging, heavy industry – have a high rate of workplace injury and death. Accordingly, the number of workplace injuries and fatalities fell substantially. Over the previous three years, the average number of deaths for April and May was seven and six, respectively. In 2020, there were four deaths  in April, and two in May. The number of injuries at work dropped from 247 in February to 184 in March then 74 in April, climbing back to 174 in May. Though this was a large reduction, it still shows that people were continuing to get injured at work, even while the workforce had shrunk.

A study of trauma admissions at Waikato hospital shows changes in the places and ways people were being hurt. The paper compared admissions from a 14-day period prior to lockdown with a 14-day period under level four. It found a 43% fall in the number of admissions. There were decreases in the number of admissions caused by traffic accidents, falls, and assaults. Some categories, such as cycling, equestrian, and pedestrian didn’t change. There were also changes to the places where people suffered injuries, with fewer incidents on the road, in water, in public places, and at sports fields. Farming, which was an essential service and therefore continued to operate as normal, saw a slight increase in the number of injuries.

The demographic which saw the biggest decrease was males, who tend to be over-represented in many of the high-risk workforces.

The flu curve flattened

As well as breaking the chain of transmission of Covid-19, the lockdown also stopped the spread of other diseases that usually require human-to-human transmission. One of these is the flu, which is estimated to kill around 400 to 500 people in New Zealand each year. The Flu Tracking site records the number of people reporting flu-like symptoms. The number of people reporting flu-like symptoms this year was much lower than in previous years. Circulation was broken by the lockdown, and while the numbers have ticked up slightly since then, the amount of flu circulating remains low.

Another factor that could have contributed to the drop in deaths was a reduction in cardiovascular disease (CVD), including heart attacks and strokes. The WHO lists CVDs as the number one cause of death globally; in New Zealand, they account for 5% of all hospital admissions. A study from the Waitemata DHB compared the number of admissions for CVDs during lockdown to the same period in 2018 and 2019. It found that there was a reduction in the number of admissions during level four. The reasons for this, however, aren’t clear. It could be that there were fewer instances of CVD during the lockdown; alternatively, there could have been the same number of instances, but fewer of them were either reported, or diagnosed, due to the lockdown.

Air pollution elevates the risk of heart disease, and as we saw in the previous article, air quality was significantly improved due to the decrease in traffic volumes. Stress is also a contributing factor to heart disease, and for some people, the lockdown was a less stressful time.

Conversely, a sedentary lifestyle raises the risk of CVD, so if people weren’t getting as active as they had been pre-lockdown, this could have had a negative effect. The strict stay at home messaging, especially for people over 70 who are the highest risk for CVD, may have led to some people being overly cautious when they were feeling unwell. Another possibility is that the lack of in-person consultations meant that many symptoms were missed by physicians.

The lockdown backlogs

With the health system focusing on Covid, many people had to wait until the lockdown lifted before they could be seen in person by their doctor. This may have meant a delay in diagnosis, or people on a waiting list having to wait even longer, such as for women with endometriosis. The NZ Association of Orthopaedic Surgeons said more than 10,000 elective surgeries were delayed. While elective surgery is generally not regarded as urgent, it would have resulted in many people living in pain and discomfort for much longer than they would have liked to.

Another example is specialist cancer treatment. This April, there were 1031 fewer cancer registrations than in April 2019 – a 47% decrease. However, the sector has been working hard since lockdown lifted, and the number of cases diagnosed is almost back to that of a normal year. Professor Diana Sarfati from Te Aho o Te Kahu, the Cancer Control Agency, said that ”since lockdown lifted we have seen a major ramping up of cancer services, with many in the sector doing weekend and evening work, as well as outsourcing, to catch up on the Covid created backlog.” By the end of July, the number of cases reported was just 2.5% below that of 2019.

Booze and other social drugs

Another indirect effect on people’s health could have come from changes in the amount and frequency alcohol was consumed. There were stories in the days before lockdown of (socially distanced) queues forming outside liquor stores, and most people could continue to buy beer and wine from their local supermarket during lockdown. The Global Drug Survey ran a study with more than 40,000 respondents across the world, including more than 3,000 from New Zealand. Of the Kiwi respondents, 20.7% reported drinking a lot more, and a further 30.2% reported drinking a little bit more than usual. This was the biggest increase of all the countries surveyed, with the global average of people drinking a lot more being 13.5%. We also recorded very high numbers of people increasing instances of binge drinking, well above the global average. Across the whole survey (data for this question wasn’t split by country) the top two reasons for drinking more were “I have more time to drink” and “I am more bored.”

While around half of Kiwis in the survey reported drinking a little or a lot more, there were also about a quarter of us who said they were drinking less, and about 30% who reported fewer instances of binge drinking. The top reasons for drinking less were having “less contact with the people I usually drink with”, and “I can’t go to the place I usually drink.” The Global Drug Survey also asked about other drug use; while New Zealand had the second lowest use of cannabis in the 12 countries participating, above only Ireland, 41% of people used more use during lockdown, while for 42% it stayed about the same. Only 16% reported a decrease in usage.

As a result of our lockdown, fewer New Zealanders will die this year. There are a number of reasons for this. There were fewer of us involved in car accidents, or incidents at work. The lockdown broke the chain of transmission for a number of other diseases, not just Covid, and this meant that fewer of us got sick.

But with the health system focussing on coronavirus, many people had their appointments cancelled or delayed, from their regular visits to the doctor, through to more serious interventions, such as elective surgeries and cancer treatment. This will place further strain on the health system, as well as the physical and mental health of those having to wait longer for treatment. Finally, the lockdown changed the way that we consume alcohol and drugs, with some of us using more, while others went the other way, removed from the places and social situations we were so used to.

In tomorrow’s concluding article in this series, we’ll look at some other impacts the lockdown had on the way we behave, and our lifestyles and wellbeing more generally.

Keep going!