How to read the daily DOH report without panicking

Published September 14, 2021, 12:12 AM

by Dr. Edsel Salvana

Each part has its own meaning

CLINICAL MATTERS

Dr. Edsel Maurice T. Salvana

Twenty thousand cases. 22,000 cases. Every day at 4 p.m., people get palpitations waiting for the release of the next Department of Health COVID-19 Bulletin. Most of the attention goes to the number of new cases, followed by the positivity rate. Beyond this, most people go on their way with minds made up that whatever it is we are doing is clearly not working. There is a lot more information in the daily bulletin that tells us how we are doing, and whether the tide is turning.

The daily case bulletin has many parts.

1. The item in the yellow box in the upper left-hand corner shows the active cases and the percentage of active cases. This is important because active cases refer to COVID-19 cases that are still in isolation and being actively medically managed. These are the cases that take up resources in the hospitals, quarantine, and isolation facilities, or cases isolating at home. A large number of active cases will translate to a high healthcare utilization, especially if a big percentage are severe or critical.

New cases reported are located right below the yellow box. These cases represent a 24-hour period of reporting between two cutoff times. This gives us an idea of how fast cases are being diagnosed in the community. These new cases weren’t necessarily infected all at the same time. Some people wait a few days from the start of symptoms before testing. Some people are diagnosed as part of contact tracing and may have been asymptomatic when tested. Some people may have already recovered at the time of testing and the test is being done for screening for travel or other purposes, and residual virus was incidentally picked up. Therefore, this number is a mix of old and new cases.

There are also cases on backlog with incomplete data, which are officially added when the case report form has been completed. This may take a few days or weeks, though with the improved current system long delays are now less likely.

2. To the right of the yellow box is the green box, detailing the number and percent recovered. This shows how many COVID-19 infected patients have survived COVID-19. Below the green box is new recoveries. New recoveries are typically time-based, pertaining to asymptomatic or mild cases that are considered recovered in 10 days. Moderate, severe, and critical cases are tagged as recovered after 21 days.

Sometimes, some people tagged as recovered later die of complications from COVID-19. These are removed from the number of recovered cases and converted to deaths in the maroon box to the right of the yellow box. The new cases less the new or daily recovered cases, less the number of deaths gives the net number of new active cases of COVID-19. It is useful for eyeballing the growth of infections over time.

3. The maroon box shows the case fatality rate (CFR) and total deaths. The CFR is currently at 1.6 percent, which is below the global average. The deaths of about 35,000 Filipinos are tragic, but in terms of per million population ranks low at 118th in the world. This is five to 10 times less than the deaths per million in the US and Europe. This is remarkable given our limited resources and our willingness to accept Filipino repatriates who have nowhere else to go.

Below the maroon box are deaths reported for the day. These deaths do not reflect deaths in the last 24 hours, but rather the deaths that were reported to the system in that time frame. Some deaths may have occurred days to weeks prior to reporting, and so these need to be eventually plotted on a graph using the actual date of death.

4. The gray middle box shows the total number of confirmed cases in the country. This is currently at about 2.2 million. In terms of per million population this is significantly below the global average. The Philippines ranks 130th in the world in this aspect, which is six times lower than COVID-19 cases per million population of the United States.

5. The first set of blue boxes on the left shows the current positivity rate and the number of tests done. The positivity rate is something to which people are drawn to since it gives an idea of the adequacy of the amount of testing being done. The daily absolute number of tests though doesn’t garner as much attention. Testing in the Philippines is currently in the 50 to 70 thousand tests per day range, which is higher than at any other time in the pandemic.

The positivity rates are high mainly because of Delta. Delta is so contagious that anyone who comes into contact with a confirmed case has a higher likelihood of testing positive compared with previous variants. More aggressive contact tracing is also being done by LGUs, such that individuals with higher probabilities of testing positive are being detected. When cases eventually go down, the positivity rate will go down naturally.

The number of tests done typically fluctuates during weekends. On Sundays, the number of cases is historically lower and these get reported on Tuesdays. So the pattern is that cases are typically low on Tuesdays, but it doesn’t mean there are actually fewer infections. For instance, if 70,000 tests are done on Saturday with a 20 percent positivity rate, the number of new cases will be 14,000 on the Monday report. But if only 50,000 tests were done Sunday with the same 20 percent positivity rate, only 10,000 cases will be reported on Tuesday. The actual infection rate in the community is probably the same, and the Tuesday result is 4,000 new cases lower because fewer tests were done. This is why it is very important to pay attention to the number of tests done. Record numbers of cases are seen on some days due to variations in the number of tests done, but this doesn’t necessarily mean the cases are going up if the positivity rate remains the same.

6. The blue box in the middle, below the total number of cases, shows the percent of mild and asymptomatic cases. These cases can usually be isolated in Temporary Treatment and Monitoring Facilities (TTMFs) and should not be admitted to hospitals, especially when healthcare utilization rates are high. Only severe and critical patients should be prioritized for admission during these times to avoid overwhelming the healthcare capacity.

7. The leftmost and middle light blue boxes in the lower third show healthcare capacity for the entire Philippines and for NCR. These show how close the hospitals are to filling up. When there are no more hospital beds for severe and critical cases, people who could have been saved with proper medical care would needlessly die.

8. The rightmost light blue box shows the percentage of asymptomatic, mild, moderate, severe, and critical cases among the current active cases. Historically, about 95 percent of active cases are asymptomatic or mild. The more seriously ill patients who need hospitalization are less than five percent of the active cases. As more and more people are vaccinated, the proportions of severe and critical cases are expected to shrink by more than 90 percent. When this happens, the hospitals will be better able to cope with the daily influx of severe and critically ill patients, even if many people are getting infected. This is because nearly 99 percent of cases by then will be mild, and only a small proportion will need hospitalization. This is what it would truly mean to live with the virus.

As a final note, without vaccination, community quarantines or public health standards, the number of cases of COVID should be going up by at least five-fold every five days since Delta’s R0 is 5 to 8. In other words, if there were 1,000 cases a day at the start, 5,000 cases would be expected by day five, 25,000 cases by day 10, and 125,000 cases by day 15. If the number of cases were to remain steady at 1,000 over 15 days, that means the virus is being suppressed by public health measures.

The current number of cases, while high, has remained at nearly the same level for nearly two weeks. This tells us the ECQ in early August probably worked. The Rt (reproductive number) is now close to 1. Otherwise, exponential growth rather than steady numbers would have resulted. As scary as the numbers look now and as heavy the toll the disease has taken on our healthcare system, these numbers were expected to be much worse (https://mb.com.ph/2021/09/07/our-lockdowns-are-worth-it-but-how-do-we-move-forward/). It would be infinitely better if the numbers were to go down as soon as possible. Given the potential of Delta to kill as many people as it did in India, however, the preemptive lockdown and accelerated vaccination did make a difference.

 

 
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