Some countries have clear advantages during a pandemic. For instance, New Zealand is surrounded by a thousand-kilometre moat.

On the other hand, Sweden’s obvious disadvantage was its proximity to Northern Italy, one of the first Covid-19 hotspots outside of China and a common destination for Swedes on ski holidays.

However, research from Washington DC-based George Mason University show it can be the less obvious shortcomings that can hurt the most during a pandemic.

In their recent working paper, 16 Possible factors for Sweden’s high Covid death rate among the Nordics, the data reveals over the last several years Sweden experienced low mortality influenza seasons and hundreds of elderly and vulnerable Swedes did not die of the flu.

As a result, Sweden’s annual mortality rate fell from 9.3 to 8.7 deaths per 1000 between the years 2016/7 to 2018/19 – a drop of 0.6 deaths/1000.

Authors Klein, Book and Bjørnskov suggest Sweden had nearly 4000 “additional” vulnerable people (or 0.4 deaths/1000) among their population of 10 million heading into 2020. They apprehensively refer to this as Sweden’s “dry tinder” situation.

Unfortunately, when countries avoid the devastation of annual forest fires for several years it can lead to one devastating year years later, or in Sweden’s case one devastating pandemic year.

Combined with a poor policy response to protect its older population, Covid-19 quickly swept through the country’s elderly citizens claiming nearly 6000 deaths, 96% of which were aged 60 or above.

The authors say it seems reasonable to us 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.”

Undoubtedly, other countries such as the US, Spain and Italy have also experienced similar high mortality rates among their elderly and vulnerable populations too. For what reasons, maybe less obvious that summary statistics reveal.

Of course, mortality is only one aspect of the Covid-19 pandemic.

Emerging research suggests that in addition to both acute and severe respiratory symptoms, Covid-19 may also cause extrapulmonary symptoms like myocardial dysfunction and arrhythmia, acute coronary syndromes, acute kidney injury and other neurological illness.

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