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Forget everything you thought you knew about this pandemic.
According to a study from the University of Edinburgh, the most effective way to reduce the death toll from Covid may be to let people spread the virus to develop ‘herd immunity’.
But what exactly does this imply?
JOHN NAISH explains …
What is collective immunity?
Herd immunity occurs when a large proportion of a population – the herd – is immune to a virus, making it unlikely to spread.
This happens either because people catch the virus (and survive) or because they are vaccinated.
This week, thousands of scientists around the world signed a letter, known as the Great Barrington Declaration, urging governments to follow this strategy – while “protecting” the vulnerable – to protect the majority of the devastating effects of the disease. locking.
This view was reinforced by the Edinburgh study.
The Edinburgh study looked at lockdown-like scenarios and found that while the lockdown could protect hospitals, it could also prolong the pandemic and prevent the build-up of herd immunity. Pictured: The green and purple lines represent deaths that could occur in a second wave, while the black line suggests the deaths would have exploded during the first wave but remained low throughout the year if the country was not locked.
What the cases and deaths would look like if the UK only isolated entire households of people with Covid-19 and locked out those over 70. The graphics to the left show how young people would have caught the virus much more easily and would have developed some herd immunity. It would also lead to fewer deaths, as shown at right, researchers say
How many must catch the virus?
Experts disagree on how many people it would take to achieve “collective immunity” with Covid.
Kate Bingham, of the Government Vaccine Task Force, said 50% of the population is all it takes, but World Health Organization chief scientist Soumya Swaminathan said at least 70 %.
Other more infectious viruses, such as measles, require rates of up to 90%.
Why was collective immunity not sought?
Initially, the government’s chief scientific adviser, Sir Patrick Vallance, said on March 12 that “we need immunity to protect ourselves in the future”.
But after Professor Neil Ferguson of Imperial College published an article warning that 500,000 Britons could die without a nationwide lockdown, the government was terrified of abandoning its original plan.
The government’s chief scientific adviser Sir Patrick Vallance said on March 12 (pictured that day) that “we need to have immunity to protect ourselves in the future”.
Why are there still doubts?
The truth is, no one knows how to drop the restrictions while protecting the vulnerable, as the continuing number of nursing home deaths seems to show even after the lockdown.
There are also concerns that collective immunity may not last forever, or even beyond a few months.
How close are we to collective immunity?
In May, Professor Gupta of the University of Oxford – the author of Barrington’s letter – published a study claiming that the coronavirus had already infected half of the British population.
But figures from random antibody tests last month suggest the actual number could be as low as 7%.
Oxford University Professor Sunetra Gupta – the author of Barrington’s letter – published a study in May claiming the coronavirus may have already infected half of Britain’s population
