The COVID-19 Pandemic: Are We Still in the Exponential Growth Phase?

The Novel Coronavirus or COVID-19 pandemic is sweeping the world. As on March 31^st, 2020 (end of day, GMT), the total cumulative number of confirmed coronavirus cases worldwide had shot up to 858,355 and the total number of deaths had increased cumulatively to 42,309. The total number of new confirmed cases on a single day on March 31st, 2020 alone was recorded at 73,617. What is the trend of daily new cases worldwide and are there any signs of the growth tapering off? In other words, has the exponential growth phase of the pandemic passed or still continuing? What about the trends in deaths due to coronavirus? In this article, I make an attempt to analyze these trends based on the relevant data for a period of 31 days from March 01, 2020 to March 31, 2020.

First, it is helpful to see how the total confirmed coronavirus cases have increased over the last 30 days (Fig.1). As can be seen, the rising trend in the total number of cases can be clearly observed. The daily new cases are also clearly showing a rising trend during this period.

Fig.1: Coronavirus cases – worldwide.

Source: The author, with data from https://www.worldometers.info/coronavirus/ (accessed on April 1, 2020).

To examine whether the growth in the total number of cases is still continuing at an exponential rate, we turn to another important variable – the growth factor of daily new cases. This factor is the ratio of number of daily new cases over the number of new cases on the previous day. Simply put, this factor indicates the rate at which a given quantity multiplies itself during a specific period. For example, a growth factor of 1.1 in daily new cases would indicate that the number of daily new cases has increased by 10% (by a growth factor of 1.1) over the number of new cases on the previous day. If the growth factor remains consistently above 1.0, that would indicate that the exponential growth phase in total cases is still continuing. On the other hand, a growth factor consistently below 1.0 would indicate a decline in daily new cases with the daily new cases eventually becoming zero. In such a scenario, the cumulative total number of cases would eventually stop growing.

Fig. 2 indicates the trend in growth factor of daily new coronavirus cases worldwide. As can be seen, during March 2020, only on 7 days (out of 31), the daily growth factor has remained below 1.0. On 24 days, the growth factor has stayed above 1.0. In the last ten days of this period, the daily growth factor has remained above 1.0 on eight days. This would indicate that the exponential growth in the total number of cases worldwide may still be continuing. 

Fig.2: Growth Factor of Daily New Coronavirus Cases – Worldwide.

Source: The author, with data from https://www.worldometers.info/coronavirus/ (accessed on April 1, 2020).

Trends in Deaths Due to Coronavirus

It is also helpful to understand the trends in deaths occurring worldwide due to COVID-19. Fig. 3 depicts this trend during March 2020. As can be seen, the total cumulative deaths due to coronavirus are still increasing and the daily new deaths also exhibit a rising trend.

Fig.3: Deaths Due to Coronavirus – Worldwide.

Source: The author, with data from https://www.worldometers.info/coronavirus/ (accessed on April 1, 2020).

To examine whether the growth in total deaths due to coronavirus is tapering off or still rising exponentially, we turn to the growth factor in daily new deaths. This is depicted in Fig. 4 below. Again, we can see that this growth factor has remained below 1.0 only on 7 days during March 2020 whereas on the remaining days, it has shown a value above 1.0. During the last ten days of the month, this factor has remained above 1.0 on nine days. Hence, the exponential growth phase in total deaths worldwide due to coronavirus may still be continuing.

Fig.4: Growth Factor of Daily New Deaths – Worldwide.

Source: The author, with data from https://www.worldometers.info/coronavirus/ (accessed on April 1, 2020).

In conclusion, as the above analysis shows, we can say that the growth in both the total number of confirmed cases and total deaths worldwide due to coronavirus may still be continuing in the exponential phase. Countries around the world have been taking massive efforts to minimize the surging infections and deaths due to this pandemic. These efforts need to be increased and carefully calibrated to deal with the massive challenge on hand.

(The views expressed in this article are personal).