Epidemiological models suggest that suppression measures like social distancing and home isolation could be in place for 18 months or longer in an effort to prevent further spreading of COVID-19, the disease caused by the virus SARS-CoV-2. In worst-case-scenario predictions, researchers suggest approximately half-a-million associated deaths in Great Britain and 2.2 million in the US, "not accounting for the potential negative effects of health systems being overwhelmed on mortality."

Such strategies are recommended to remain in place until vaccines are made available to the general public, according to a report conducted by the Imperial College of London COVID-19 Response Team in collaboration with infectious disease experts. Though US researchers are in the early stages of clinical trials, the US Food and Drug Administration requires several parameters to be met to first prove that a vaccine is safe and effective in both small and larger population studies before it is available to the general public. Current estimates suggest that a vaccine won’t be available for one to two years.

The report authors write that COVID-19 is the most serious public health threat seen since the 1918 Flu Pandemic. At the time of publication, a situation report published by the World Health Organization confirmed more than 167,000 global cases, resulting in more than 6,600 deaths – nearly half of which have occurred within China. Due to the rapidly evolving nature of the virus and the information available, those numbers are changing hourly.

Based on data currently available, modeling experts found that the effectiveness of any one intervention on its own is likely to be limited and instead requires multiple intervention strategies to be used simultaneously. Two fundamental strategies are at play for hindering the spread of the virus: mitigation, which focuses on slowing the spread by quarantining infectious individuals, and suppression, which aims to reduce transmission by isolating those who are not infected.

“We find that that optimal mitigation policies (combining home isolation of suspect cases, home quarantine of those living in the same household as suspect cases, and social distancing of the elderly and others at most risk of severe disease) might reduce peak healthcare demand by 2/3 and deaths by half,” write the authors.

“However, the resulting mitigated epidemic would still likely result in hundreds of thousands of deaths and health systems (most notably intensive care units) being overwhelmed many times over.”

In a White House press conference Tuesday morning, Dr Deborah Birx, a physician appointed to serve as the COVID-19 response coordinator for the White House Coronavirus Task Force, said the estimated number of deaths is higher than any her office has seen and plans to host a meeting Wednesday to address the report and evaluate data to create models more specific to the US. Suppression has been adopted by several countries around the world. China, Italy, Spain, and France have already put lockdown measures in place, while San Francisco has issued a “shelter in place” until April 7. Around the world, major events have been canceled and schools closed in order to halt the disease while scientists attempt to find treatments and hospitals scramble for resources.

“The study paints a sobering picture with marked differences to previous estimates, showing clearly that mitigation will not only be insufficient to prevent the NHS becoming overwhelmed, but also has little impact on the overall numbers of severe cases and deaths over time,” commented Dr Stephen Griffin, associate professor at Leeds Institute of Medical Research and the University of Leeds. Griffin was not involved in the study.