Sweden is debating enforcing new coronavirus restrictions on Stockholm amid a small spike in infections.
The country's chief epidemiologist Anders Tegnell — who advised Sweden to avoid full lockdown in favour of a 'herd immunity' strategy — said new measures for the capital could not be ruled out.
It came just hours after the city's top health official warned the region, home to more than 2million people, had seen its downward trend 'broken'.
The news will prompt questions over whether Sweden has achieved 'herd immunity' or not — even though different regions can have differing levels of protection. One coronavirus expert from Denmark yesterday suggested Sweden's crisis could be 'over'.
The country is currently recording around 28 infections per 100,000 people. This figure is less than half of the UK's own infection rate of 69, which has risen drastically over the past three weeks.
Meanwhile, Professor Tegnell claimed the country's success in battling last year's winter flu has been the cause for its high coronavirus death toll. The elderly are the most vulnerable to both diseases.
Sweden's chief epidemiologist Anders Tegnell (pictured) said new measures for the capital could not be ruled out
At the peak of the crisis, Stockholm county was recording around 240 cases a day. This has dropped to below 100 by the start of July but has now started to risen to an average of around 44 — up from 30 a fortnight ago
Herd immunity is a situation in which a population of people is protected from a disease because so many of them are unaffected by it - because they've already had it or have been vaccinated - that it cannot spread. To cause an outbreak a disease-causing bacteria or virus must have a continuous supply of potential victims who are not immune to it.
Immunity is when your body knows exactly how to fight off a certain type of infection because it has encountered it before, either by having the illness in the past or through a vaccine. When a virus or bacteria enters the body the immune system creates substances called antibodies, which are designed to destroy one specific type of bug.
When these have been created once, some of them remain in the body and the body also remembers how to make them again. Antibodies - alongside T cells - provide long-term protection, or immunity, against an illness. If nobody is immune to an illness – as was the case at the beginning of the coronavirus outbreak – it can spread like wildfire.
But if, for example, half of people have immunity – from a past infection or a vaccine – there are only half as many people the illness can spread to. As more people become immune the bug finds it harder and harder to spread until its pool of victims becomes so small it can no longer spread at all.
The threshold for herd immunity is different for various illnesses, depending on contagion.
Sweden's strategy emphasising personal responsibility rather than major lockdowns to slow the virus drew fierce criticism as deaths shot up in spring. Critics warned how thousands of patients could die.
Infections dropped significantly in the summer and they had been spared the type of sharp increases in new cases seen in Spain, France and Britain this month.
And the country is currently recording fewer than 200 new cases a day, on average — a figure which has dropped from around 250 last week.
For comparison, the country was recording around 1,000 infections daily during the peak of its crisis in June.
It was also announcing more than 100 deaths a day, during the darkest weeks of the crisis — suggesting tests were only picking up a fraction of the disease, given the virus is estimated to kill around 0.6 per cent of infected patients, many of whom are unaware they have the disease.
Sweden has only recorded 31 deaths throughout the entire month of September, and the daily totals have stayed in single figures since July. Patients can take around 21 days to die of the disease, meaning any true spike in cases is seen in deaths several weeks later.
These figures have bolstered claims that