When you think of Sweden, does Abba come to mind? What about meatballs or furniture stores? Maybe that was true in 2019. These days, Sweden is more likely to split friendships over arguments about herd immunity and its Covid-19 death toll.

To date, there has been no shortage of commentary from the public and experts about Sweden’s controversial approach to coronavirus. Many commentators have hastily concluded which country has had the best response, yet no one, neither experts nor the public, have the full story just yet.

At best, this world-wide pandemic is only halfway finished and crucial questions about the virus – herd immunity and its short- and long-term health impacts – remain unanswered.

But what do the numbers and the research say about Sweden’s response so far? And what factors contributed to Sweden’s widely publicised high mortality rates?

To help explain those rates, researchers from Washington DC-based George Mason University offer an early answer using the analogy of “dry tinder” and pent up forest fires.

Every year, many countries experience forest fires and hundreds of thousands of elderly and vulnerable people die from influenza. This is an unfortunate truth but a fact. And it must be considered when comparing this year’s Covid-19 mortality rates.

But what happens when a country has a few light influenza seasons in a row? Just like branches gathering on the forest floor, the result is a build-up of “dry tinder.” Should a fire start, or a new coronavirus emerge, the consequences will appear more devastating since the pain happens all at once.

At least this is what authors Klein, Book and Bjørnskov cautiously suggest happened in Sweden in their latest working paper, 16 Possible factors for Sweden’s high Covid death rate among the Nordics.

In the years before 2020, Sweden experienced several low mortality years which avoided the deaths of hundreds of elderly or vulnerable Swedes. Out of the 13,324 people infected during the 2018-19 influenza season, 505 Swedes died within 30 days compared to 734 during the 2016-17 season, and only 261 during the 2015-16 season.

In the graph on the left, the dashed red line shows this lower influenza mortality rate in the years 2018 and 2019. And in the figure to the right, the gold line shows the total annual deaths (from all causes) fell from 9.3 to 8.7 deaths per 1000 in the years 2016/17 to 2018/19 – a drop of 0.6 deaths per 1000 Swedes. Comparatively, Sweden’s neighbours Denmark, Norway and Finland experienced little to no change in their annual mortality rate in the same years.

This means Sweden had nearly 4000 “additional” vulnerable individuals (or 0.4 deaths/1000) in their population of 10 million heading into 2020. This “dry tinder” situation may have helped create Sweden’s unusually high mortality rate during the Covid-19 pandemic.

The authors said it seems reasonable that “the dry-tinder factor could account for 1500 to 3000 of Sweden’s ‘Covid deaths’ during the whole of 2020, or between 25-50% of Sweden’s Covid death toll as of mid-August.”

Of Sweden’s nearly 6000 Covid-19 deaths, 96% were aged 60 or above. About 26 percent of deaths were older than 90, while 41.5 percent were in their 80s, 21.5 percent in their 70s and 6.9 percent in their 60s. The same trend has played out in the United States and Europe.  

That is not to say those Covid deaths were avoidable. The authors suggest other factors that contributed to Sweden’s higher death toll, including the country’s:
•    greater proportion of people in elderly care;
•    slower reaction to separate Covid patients in nursing homes;
•    poorer attempts to try and cure elderly Covid patients; and
•    its slow reaction to implement staff testing and changes in protocols and equipment.

Even Sweden’s chief epidemiologist Dr Ander Tegnell admits there were too many deaths. Yet, he also emphasised that this “does not disqualify our strategy as a whole.”

The stats show Sweden did register a moderate increase in excess deaths at the peak of the pandemic. However, this was much smaller than in the UK and Spain. Compared to its Nordic neighbours, however, Norway, Finland and Denmark did not see a similar increase in excess deaths.

Source: https://www.euromomo.eu/graphs-and-maps

What the George Mason University report highlights is that some countries have significant disadvantages during a pandemic that are not obvious when looking at raw statistics. Those shortcomings matter quite a bit.

It also highlights that some disadvantages or advantages are more obvious than others. New Zealand’s major advantage is being an isolated island nation at the bottom of the world, four hours by jet plane from the next country. Sweden, on the other hand, had the serious disadvantage of being within a hours’ flight of Northern Italy, one of the first Covid hotspots outside of China and a common destination for Swedes on ski holidays.

It was obvious that Covid-19 would spread through airline travel. What was less obvious is that Sweden’s “dry tinder” build-up before the Covid-19 pandemic made this pandemic particularly deadly for the country. It is wrong to blame Sweden’s results entirely on its lighter lockdown.

What can be learned from all this? The Swedish case study shows the importance of policies that reduce the risk for those most at risk of contagious viruses. It also reinforces the need for all health officials to understand and highlight their country’s hidden disadvantages or advantages.

Of course, mortality is only one aspect of the Covid-19 pandemic. While it was already well known that elderly folk are more at risk of dying from an infection, less is known about the short- and long-term health impact for younger people who were infected by Covid-19 and recovered.

Emerging research shows that in addition to both acute and severe respiratory symptoms, Covid-19 has caused extrapulmonary symptoms including thrombotic complications, myocardial dysfunction and arrhythmia, acute coronary syndromes, acute kidney injury, gastrointestinal symptoms, hepatocellular injury, hyperglycemia and ketosis, ocular symptoms and dermatologic complications.

Other research shows significant neurological consequences among hospitalised patients months after infection.

With nearly 85,000 confirmed cases in Sweden, it may be more than just the elderly who have paid a serious price for a chance at herd immunity.