Mass lockdowns and widespread social distancing may have prevented 59,000 Covid-19 deaths, according to a new model from Imperial College in London.
A team of researchers – including Neil Ferguson, whose projections helped inform the British government’s response to the outbreak and Samir Bhatt – estimated that tens of thousands of lives had been saved in 11 countries as a result of measures such as case isolation, school closures, bans on mass gatherings as well as local and national lockdowns.
The measures had a “substantial impact in reducing transmission” for countries with more advanced epidemics, with an estimated 38,000 deaths averted in Italy and 16,000 in Spain, but it is “too early to be sure” about similar reductions for countries in the earlier stages of the outbreak, researchers said.
Most countries in the model – Austria, Belgium, Denmark, France, Germany, Norway, Sweden, Switzerland and the United Kingdom – began their interventions between March 12 and 14.
“While we cannot determine which set of interventions have been most successful, taken together, we can already see changes in the trends of new deaths,” the researchers said.
“We note that substantial innovation is taking place, and new, more effective interventions or refinements of current interventions, alongside behavioural changes will further contribute to reductions in infections.”
The report, published on Monday, also estimated that between 7 and 43 million people had been infected in the 11 countries by late March – somewhere between 1.88 per cent and 11.43 per cent of the population – and said a large number of cases had probably gone unreported.
On average, the proportion of the population infected in the assessed countries was 4.9 per cent, with the highest estimates in Spain and Italy, and the lowest in Germany and Norway.
The coronavirus that causes Covid-19 first began to spread late last year in central China, but has since become a devastating global pandemic, with the most confirmed cases in the United States, Italy, Spain, Germany, France and mainland China.
A separate study by Ferguson and other researchers, including Imperial College epidemiologist Azra Ghani, published on Monday in The Lancet found that the overall case fatality ratio for Covid-19 was lower than estimates for the severe acute respiratory syndrome (Sars) and Middle East respiratory syndrome (Mers) coronaviruses, but “substantially higher” than those of recent influenza pandemics such as the H1N1 influenza in 2009.
“With the rapid geographical spread observed to date, Covid-19 therefore represents a major global health threat in the coming weeks and months,” the researchers said.
“Our estimate of the proportion of infected individuals requiring hospitalisation, when combined with likely infection attack rates (around 50–80 per cent), show that even the most advanced health care systems are likely to be overwhelmed.
“These estimates are therefore crucial to enable countries around the world to best prepare as the global pandemic continues to unfold.”
The study also found that the risk of death increased significantly for individuals in older age groups, although they noted early results indicate children are not at a lower risk of infection compared with adults.
Using data from China, researchers estimated the overall case fatality ratio to be at 1.38 per cent, with a lower ratio of 0.32 per cent for under-60s, compared with 6.4 per cent for over-60s and rising to 13.4 per cent for people who were over 80.
“It is clear from the data that has emerged from China that case fatality ratio increases substantially with age,” they said.
The age gradient was also observed in cases outside China, where the fatality ratio was estimated at 1.4 per cent for people under the age of 60, compared with 4.5 per cent for those 60 and over.
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