Image: Tina Tiller
Image: Tina Tiller

ScienceDecember 21, 2021

For many New Zealanders, Covid-19 will be a lifelong disease

Image: Tina Tiller
Image: Tina Tiller

Research into long Covid is in its infancy, but early indications suggest thousands of people will be unable to work months after contracting the virus.

“Now we have to talk about your quality of life.” I was 21 years old, sitting in a doctor’s office for the 13th time in 12 weeks, and I was being diagnosed with post-viral chronic pain and fatigue syndrome. What had started as an innocent sinus infection had turned into pain that never went away and the kind of fatigue that had me hallucinating on a daily basis, even though I slept for upwards of 12 hours a day. 

I almost laughed out loud. Quality of life was a term used in hospices, wasn’t it? It felt ridiculously out of place. It felt like I had opened someone else’s mail. This wasn’t supposed to be happening to me. 

Six years later and I still have fibromyalgia. I also feel like I’m staring down a wave of chronic illness that is hitting millions of people across the world and is about to hit us here. When the delta strain of Covid-19 finally broke through the barriers we had spent 18 months building up, I couldn’t stop thinking about long Covid in New Zealand.    

I work for an actuarial consulting company, which basically means we help insurance companies manage risk. Covid-19 is something that health insurers, life insurers and those who provide income replacement policies have to think about. With this in mind, I suggested we look into how long Covid would play out in Australia and New Zealand in the near future. This is what we found.

Case numbers

As a starting point for our analysis, we took the case numbers from Te Pnaha Matatini, a research institute that has informed the New Zealand government’s response to the pandemic.

They projected infections over the next year under a range of scenarios which differ on:

          The proportion of people vaccinated.

          How effective the vaccine is.

          The level of public health measures in place (e.g. restrictions on large gatherings).

          How well the test, trace, isolate and quarantine (TTIQ) systems are functioning.

When New Zealand moved to the traffic light system on December 3, 86% of the eligible population was fully vaccinated.

For our analysis, we decided to go with the 90% vaccinated scenario from Te Pnaha Matatini, along with central vaccine effectiveness – meaning neither the most pessimistic nor optimistic estimates – and baseline public health measures. 

While the government is insistent that contact tracing is able to keep up with demand and home isolation is working well, other signs point to a system that is struggling. A report from the Covid-19 Independent Continuous Review, Improvement and Advice Group (IAG) stated that the capacity of contact tracers would begin to diminish during a prolonged period of 100-200 cases per day. Given that case numbers have sat in this range for many weeks at a time, we chose the limited TTIQ scenario.

Under the selected scenario, Te Pnaha Matatini projects 972,073 Covid-19 infections in a 12-month period. This includes asymptomatic and undetected infections. Based on international projections of asymptomatic versus symptomatic infections, we believe that this would result in approximately 220,000 symptomatic infections being detected in New Zealand.

Of these, we believe that about 105,000 will be vaccinated and 115,000 will be unvaccinated. This means that 2.7% of the vaccinated population will contract Covid, while 9.6% of those who are unvaccinated (or under 12 and ineligible) will catch it. 

Hospitalisations

Hospitalisation not only adds pressure to the healthcare system, it also has a strong impact on the projections of long Covid. The more severe your infection, the likelier you are to experience long Covid.

Based on current national rates and international evidence on the difference in hospitalisation rates between vaccinated and unvaccinated individuals, we project that 4.7% of all symptomatic cases will be hospitalised. For those who are vaccinated, the estimated rate of hospitalisation is 1.4%, while for those who are unvaccinated, it is 7.8%. Children under the age of 12 are included in the unvaccinated figures, and kids are much less likely to be hospitalised than adults. So for unvaccinated adults, the risk is higher than this number suggests.

Of the 220,000 symptomatic cases, we project that 10,500 will end up in hospital, and 1,300 will end up in the ICU. Taking the average cost of a night in hospital and ICU in New Zealand, and the length of time that someone with Covid tends to be hospitalised for, we expect that this will cost the public healthcare system about $158 million in the next year.

While almost half of Covid infections are expected to occur in those who have been vaccinated, we expect that only 14% of hospitalisations and 19% of ICU admissions will be for vaccinated individuals.

Long Covid

Long Covid is becoming more relevant as we realise just how many people seem to experience some degree of symptoms for months after the initial infection. Research into long Covid is in its infancy and we don’t know how long these symptoms will continue, in part because enough time hasn’t gone by. Anyone looking at our projections should bear in mind the uncertainty that exists in this area. However, we do have some initial indications of what to expect.

Research suggests that 27% of those with a symptomatic infection and 50% of those who are hospitalised will have a post-Covid condition at 30 days. This means that they are still experiencing some symptoms a month on, most commonly pain, breathing difficulties, hyperlipidaemia (high cholesterol) or fatigue. We can combine this with evidence that of those people who are experiencing symptoms at 30 days, 45% will be working reduced hours seven months down the road due to long Covid, while an additional 22% will not be working at all.

Vaccination does seem to cut the risk of long Covid in half, along with reducing the risk of catching Covid in the first place and reducing the risk of hospitalisation.

We expect that 22,000 people in New Zealand will have long Covid such that they would need to work reduced hours seven months after the acute infection, and an additional 10,700 would need to stop working completely.

These numbers include people who are not working (e.g. children, students, stay at home parents, unemployed and retired people), so could be more accurately thought of as moderate and severe impairment due to long Covid. Our projections indicate that 6.3% of vaccinated cases and 13.2% of unvaccinated cases will experience moderate impairment, and 3.1% of vaccinated cases and 6.5% of unvaccinated cases will experience severe impairment seven months after infection.

Among the working age population (aged 18-65) we expect that 13,700 New Zealanders will be moderately impaired and 6,800 will be severely impaired due to long Covid, seven months after they initially caught the virus. In both cases, unvaccinated individuals make up just over 60% of all long Covid cases, despite being only 10% of the adult population. 

Conclusion

Until now, the health impacts of Covid-19 on New Zealand have been much more limited than in other countries. That is changing, and for some, this will not be a short-term acute infection that is completely resolved after a few weeks.

Many of us who have conditions that are similar to long Covid hope that more research, better treatment and an awareness of chronic illness will come out of this pandemic. We also know how difficult things are about to get for those people who develop long Covid.

So how is my quality of life now? Probably better than that doctor expected. I manage my condition through a combination of medication, exercise, and having the kind of sleep schedule that most 20-somethings would laugh at. I don’t hallucinate because of fatigue anymore, and I have some pain-free days. But put it this way: if I could only change one thing about my life, this reality would be it.

Since the pandemic began, I’ve been significantly less worried about the acute illness that Covid can cause, and much more worried about the long-term impacts of getting sick. The risk might be small, but when we roll that dice hundreds of thousands of times, you don’t need to be an actuary to know that thousands of people will lose. So I am asking you to give yourself the best odds, get vaccinated, wear a high quality mask, and take any other precautions you can to protect yourself.

The Spinoff’s science content is made possible thanks to the support of The MacDiarmid Institute for Advanced Materials and Nanotechnology, a national institute devoted to scientific research.

Mad Chapman, Editor
The Spinoff has covered the news that matters in 2021, most recently the delta outbreak. Help us continue this coverage, and so much more, by supporting The Spinoff Members.Madeleine Chapman, EditorJoin Members

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