Without any containment measures, the coronavirus could kill 40 million people

The 1918 flu pandemic is estimated to have killed more than 40 million people, the same amount of people could die from the COVID-19 disease if no measures were taken to contain the virus. These are the results of a report published by Imperial College London on 26 March and produced by a team of mathematical modelling experts.

The report also indicates that, without preventive measures, 90% of the world’s population would have been infected with the SARS-Cov-2 virus. For the researchers, how individual governments respond to the health emergency in the coming weeks will be critical in slowing the trajectory of the epidemic in each country.

The analysis

It must be kept in mind that we are dealing with an unknown virus and that there are still many details that we do not know about its transmission and evolution over time, as well as the very different social, economic and demographic circumstances in each country, so there is always a high degree of uncertainty in the predictions of developed mathematical models. In any case, the results of this and many other analyses always have an impact on the need to implement prevention strategies to avoid health collapse in the most affected countries.

In this study, the expert team combined age-specific data on contact patterns and disease severity to project the impact of the pandemic in 202 countries. In particular, predicted mortality impacts in the absence of interventions were compared with those that could be achieved through policies to mitigate or suppress transmission.

The authors caution, however, the "estimates of mortality and demand for health care are based on data from China and high-income countries. Differences in underlying health conditions and the capacity of the health system are likely to lead to different patterns in low-income settings".

Mitigation scenarios

The report analyses the impacts of implementing different strategies for containing the virus. Those that focus on protecting older people by reducing their social contact by 60% and slowing down but not interrupting transmission (40% reduction in social contacts for the whole population) could reduce mortality by half (in a global scenario we would talk about 20 million deaths). However, the researchers stress that, even in this scenario, health systems around the world would be rapidly overwhelmed. Moreover, the lowest-income countries would, of course, be the most affected by the collapse.

If we project a scenario in which more forceful measures are taken, involving social distancing, early detection of cases and isolation of infected persons, and also when the mortality rate in each country is 0,2 per 100,000 people per week, 38.7 million lives could be saved. If these strategies are initiated when the number of deaths is higher (1.6 deaths per 100,000 people per week) 30.7 deaths would be avoided.

"Therefore, our analysis suggests that the demand for medical care can only be kept within manageable levels through the rapid adoption of public health measures to suppress transmission, similar to those being taken in many countries today", the researchers summarise.

Another point raised by the report is the need to maintain containment measures in some way until effective vaccines or treatments are available, or else new outbreaks of VOC-19 could occur. "Our analysis highlights the very difficult decisions that all governments will face in the coming weeks and months, but it also shows how fast, decisive and collective action could save millions of lives," they conclude.