This week in 1918 NZ reached peak mortality during flu pandemic - how it compares to COVID-19

This week in 1918, around 9000 people in New Zealand died from the influenza pandemic, compared to 40 deaths so far linked to COVID-19. 

The 1918 influenza pandemic, also known as the Spanish Flu, was sparked by the spread of the exceptionally deadly H1N1 influenza A virus, which is estimated to have killed 50 million people worldwide near the end of World War I. 

It was 100 years later when the deadliest respiratory virus pandemic since the Spanish Flu took hold: the ongoing COVID-19 pandemic, which began in December 2019 and is caused by the virus SARS-CoV-2. It has so far claimed more than 5 million lives. 

Similar to 1918, Māori have been disproportionately affected. Māori make up 43 percent of all COVID-19 cases, despite representing about 15 percent of the population. In 1918, Māori had a death rate more than eight times that for Pākehā. 

The glaring difference between the two pandemics is vaccination. Less than two years since COVID-19 reached New Zealand, more than 90 percent of the eligible population have had at least one dose of the Pfizer vaccine. 

Pfizer said on Monday its COVID-19 vaccine provided strong long-term protection against the virus in a late-stage study conducted among adolescents. It said two doses of the vaccine was 100 percent effective against COVID-19, measured seven days through over four months after the second dose.

Ministry of Health data released earlier this month showed cases of COVID-19 hospitalisations were almost entirely unvaccinated people. COVID-19 Response Minister Chris Hipkins has said the virus is "morphing into a pandemic of the unvaccinated".

In 1918, there was no such inoculation available. There were also no antiviral drugs like there are today and no antibiotics to treat the secondary bacterial infections. Therefore, doctors would rely on a random assortment of medicines with varying degrees of effectiveness, from aspirin for pain relief to herbal medicines. 

"A particularly distressing consequence of infection was that it turned the skin of some of the victims purple-black," NZ History notes. "This was due to pneumonia, which attacked the lungs after the initial infection and was responsible for most of the deaths."

There was one method of controlling the virus that translated across the century: lockdowns. According to NZ History, "ordinary life ground to a halt as the pandemic peaked" in 1918, with schools and many workplaces shut to stop the spread of the virus. 

"Preventative measures included restricting the opening hours of public facilities and postponing or cancelling events that would have brought large numbers of people together - including Auckland's celebration of the armistice with Germany."

A newspaper clipping from 1918 showed instructions from the New Plymouth Public Health Committee to volunteer nurses or family attendants dealing with influenza. Like today, patients were ordered to be isolated for 14 days. Mask wearing was also common.

Researchers at Auckland University's Te Pūnaha Matatini recently found that had New Zealand not bothered to lock down when COVID-19 arrived on our shores in March 2020, it could have infected a third of the population and killed more than 30,000.

One of New Zealand's saving graces was shutting the international border and requiring returnees to spend two weeks in managed isolation facilities (MIQ) - the length of the virus' incubation period. 

The Delta strain of the virus was transported to New Zealand in August via a traveller from Sydney, around the time when quarantine-free trans-Tasman travel was temporarily permitted. 

The first known COVID-19 case was a market vendor in the Chinese city of Wuhan, according to a recent study published in the journal Science, and it soon spread via international flights from China. But how the Spanish Flu arrived in New Zealand is unclear. 

At the time, many believed that the virus had arrived on a ship which birthed in Auckland in October 1918 after sailing from Vancouver via San Francisco, according to NZ History. 

But historian Geoffrey Rice's analysis of death certificates revealed that peak mortality in New Zealand probably occurred in late November - several weeks later than would have been expected if the vessel had brought the virus, given its incubation period.

What is known is that New Zealand brought the virus to Samoa via a cargo ship in November that year, which led to the deaths of between one-fifth and one-quarter of the population. 

Influenza continues to be a significant public health issue in New Zealand, affecting up to 20 percent of people each year and causing some 500 deaths annually.