An important projection study that helped persuade the British government to take stricter measures to contain COVID-19 painted a worst-case picture of hundreds of thousands of deaths and overcrowded health services.
In a sharp tightening of the British approach to Monday's outbreak, Prime Minister Boris Johnson shut down social life in the world's fifth largest economy and advised over-70s with underlying health problems to isolate themselves.
The model study by a team led by Neil Ferguson, professor of mathematical biology at Imperial College London, used new data from Italy, where the epidemic of infectious diseases has increased significantly in recent weeks.
The Ferguson team compared the potential impact of the COVID-19 epidemic with the devastating flu outbreak of 1918 and said that without mitigating measures, the outbreak could have caused more than half a million deaths in the UK and 2.2 million in the United States.
Even with the government's earlier plan to control the outbreak, which included isolating suspicious cases at home but not restricting society, this could have resulted in 250,000 deaths and health systems many times over.
With the measures described – including extreme social distancing and advice to avoid clubs, pubs and theaters – the curve and peak of the epidemic could be flattened, the scientists said.
"This will put tremendous pressure on us as a society and economically," said Azra Ghani, Professor of Infectious Diseases Epidemiology at Imperial, who led the work with Ferguson.
Tim Colbourn, an expert on global health epidemiology at University College London, said the projections in the study signaled "hard times."
"The results are sobering," he said.
This study helped change the position of the UK government, according to those involved in the decision. The government said it had accelerated its plans to "the advice of the experts" and the new measures were always "part of the government's action plan".
"We continue to follow science and follow the advice of experts. This means that we will implement these more extensive measures a little faster than originally planned," said the source.
Johnson's government had been criticized by some public health experts who were concerned that Britain was not acting quickly or vigorously enough to curb the spread of COVID-19, while other countries such as Italy, Spain and France were taking far more draconian measures to block them.
Peter Piot, director of the London School of Hygiene & Tropical Medicine and specialist in viruses and epidemics of infectious diseases, said, however, that the UK approach is "solid evidence-based" and "strikes a balance between addressing the current public health crisis and "forth the diverse and complex social implications. "
"In this unprecedented pandemic, caused by a virus we know so little, there is no one-size-fits-all approach to control it," said Piot. "We should be open to adapting the response to an ever-changing epidemic and improving the rapidly developing scientific understanding."