COVID-19 peak could be delayed until November with social distancing

By Dr. Ananya Mandal, MDMar 31 2020

With the world reeling under the effects of the global pandemic of SARS-CoV-2 infection, that causes COVID-19 disease, the numbers have been steadily rising over the past couple of months. As of today, there have been 857,487 reported cases around the world, with the global death count now at 42,107. While these numbers are alarming, a group of experts has predicted that we are far from seeing a peak effect of this infection, and if the present measures of social distancing work, the peak of the epidemic in New South Wales, Australia would be less severe and occur in November.

Researchers from the University of Sydney, Monash University and James Cook University, have published their study titled, “Modelling the impact of COVID-19 upon intensive care services in New South Wales,” in Medical Journal of Australia.

Social distancing. Image Credit: eamesBot / Shutterstock

What was this study about?

With the rising number of cases of COVID-19, there have been 4.707 cases of the disease and 20 deaths in Australia. New South Wales remains the most reported area in the nation. The country has been under lockdown to enforce social distancing. The researchers used mathematical models to compare the data gathered from Australia and well as the United Kingdom to see the burden the disease would be on the intensive care units and the effects of the disease in the near future.

The researchers wrote, “Under the scenario of increased social isolation, the peak infection will shift to early October and peak ICU utilization will shift to mid-November and would be around one-third the size of the business-as-usual peak.”

What was done?

For this study, the team used a complex mathematical model to estimate the demands for intensive care unit beds associated with COVID-19 in the different local health districts of New South Wales. There were essentially two ways the analysis was done; the team wrote. The first method was to use an “individual-based simulation model,” as is being used in the UK. This was applied to the NSW population based on their age. The second approach was to analyze a “compartmental model,” which was again applied to the population in New South Wales. From both analyses, the team looked at the number of hospitalizations and the highest demands for ICU beds when several strategies were in place to reduce them.

What was found?

The team wrote that when they applied the UK model, the peak demands for ICU beds among the population of New South Wales was around 6,965 ICU beds. They add that this was after an “intensive mitigation strategy.” The mitigation strategy was to increase the ICU bed capacity by 797 percent before the COVID-19 pandemic hits hard in the region. Using the second analysis technique, the team noted that if 584 percent of ICU capacity was built before the onset of the peak, and transmission was reduced by one third before the peak, at least 5,109 ICU beds would be necessary.

The team writes that restrictions in movement can reduce the reproduction rate of the virus by 1.6, meaning that every individual with the infection can infect 1.6 others. If this were that case, even then, the immediate availability of ICU beds would not be sufficient, say the researchers. They explain that with 5 percent of the population needing the ICU beds and showing symptoms, there would be 14,000 people admitted to the hospitals and 5,100 patients admitted to intensive care.

They added that before this epidemic, there were 874 intensive care beds in NSW. This meant that even if the current facilities were doubled by the time the peak hit the region, there would still be a substantial shortage from the peak necessity. They write that both hospitals and ICU facilities would be “overwhelmed unless transmission can be reduced significantly.”

How can social distancing help?

With such grim figures, the researchers calculate that in order to meet the requirements of the peak needs of ICU and hospital beds, social distancing is needed to prevent transmission. They explain that if the transmission chain was not broken, the peak would be earlier – in late June, for example. Peak hospitalization would be in early July. With cutting down on transmission by one third, the peak could be less severe and hit the region in around November.

At present, there are signs that the curve of transmission is flattening in Australia. However, it is not enough, write the researchers. If present conditions persist, 16 percent of the population will develop symptoms of the disease, and over 35,000 persons would need to be hospitalized, and 11,800 intensive care beds would be needed to meet the demand. This expectation is 1,349 percent of the present capacity, they write.

At present, other than family or household members, no more than two persons are allowed to gather in public places for all of Australia, and students are requested to stay at home if possible. Employees are also requested to work from home where possible. Elderly persons over the age of 70 years and those with long term ailments are advised to stay at home unless absolutely necessary.

The authors admit that their second method of analysis – the compartment model may not be absolute because the reproduction rate cannot be firmly predicted. They also wrote that present mitigation strategies are vital in bringing the requirements down. “The present report does not estimate the effect of more intensive suppression strategies which would be likely to reduce the peak ICU requirement,” they add.

Conclusions and implications

The authors of the study conclude that both their analytical models predict a significant burden of COVID-19 on intensive care services. They wrote, “Modelling is an important tool to assist policymakers and the public to understand the impacts pandemic diseases.” The present approaches to reduce transmission and increasing the critical care services remain vital to prevent overwhelming the healthcare services they concluded.