On March 6, the cumulative number of cases doubled to four, and then on March 9 more than quintupled to 23. When the World Health Organization (WHO) elevated the epidemic to a pandemic on March 11, the cases in two days more than doubled to 48. By then, it was already obvious that the country will be hit hard. On March 17, when the enhanced community quarantine (ECQ) became effective in the whole of Luzon, there were already 186 cases.
The first case of positive Covid-19 in the Philippines was detected on January 30 and the first death was reported on February 1. The number of cases remain two, both of which are non-Filipinos, for the rest of February, so that it seemed that the Philippines will not be hit by what was still then an epidemic.
While the cumulative number of cases will only increase, the key to further understand the data is to look at the additional cases per day—i.e., the first difference or the first integration in economics parlance. Still, the number of cases fluctuates daily. In finance and in time series, scientists and practitioners try to understand erratic series of numbers by smoothening the data using moving averages (MA). For example, stock market players often use MA to eliminate idiosyncratic changes and capture the long run trend or the secular data. Known examples of applying the MA on Covid-19 include the New York Times 5-day MA and John King of CNN’s 7-day MA. Suppose we use halfway of the one to 14 days of incubation in accordance to WHO, which conveniently translates to a week.
The number of incidences and admittances to the hospital began on March 20 with the cumulative cases increasing at an increasing rate. On April 3, the incidences and admittances per day peaked at 316 and 171, respectively. On April 5, the incidences and admittances per day declined to 261 and 143, respectively, on April 6 increased to 302 and 162, and then decreased for four consecutive days. On April 7, it has become statistically official that we have passed the apex of incidences and admittances per day. April 7 was also the date that the number of recoveries then at five per day started to pick up. It was also the date that President Duterte decided to extend the ECQ to April 30.
A key scientific question was whether the incidences and admittances per day would move in cycles or permanently decline. It turned out that these will cyclically decline. These numbers will continue to decline and reach what mathematicians call the local minimum on April 10 with 168 and 91 incidences and admittances per day, respectively. On April 13, for the first time, the number of recoveries per day at 24 topped the number of deaths per day at 22. On the same day, the incidences and admittances per day became statistically officially on the upswing again; this is mere proof that the decision to extend the ECQ about a week before was right.
On April 17, the incidences and admittances per day reached its new peak or what mathematicians call the local maximum with 241 and 126, respectively. It would be the infamous date when the 7-day-MA number of deaths per day peaked at 24. On April 19, the incidences and admittances per day would be statistically officially on a downswing and the number of recoveries per pay, which stood at 54, peaked.
If trends remain, which in likelihood will not, April 24 will be the day that the 43 recoveries per day will top the 39 admittances per day. It will mark the peak when hospitals are most distressed. After that, the net number of patients in hospitals will start to decline. It will be the day our medical frontliners’ work will start to “ease” for lack of better term.
On April 24, the sum of the number of new deaths and recoveries of 10.5 will top the number of new incidences at 10.1. The number of active Covid-19 positives will peak at 6,468 and decline from then on. On May 2, for the first time, the number of recoveries per day at 4.57 will be greater than the number of incidences per day at 4.49. The healing process of the nation will begin. But that is if trends remain. That is if conditions remain the same. But ECQ and post-ECQ are totally different.
Luis Dumlao, PhD, is the Dean of the John Gokongwei School of Management, Ateneo de Manila University.