COVID-19: New evidence of data inefficiency puts into question recent gains against the virus

Warren de Guzman and Edson Guido, ABS-CBN News

Posted at Sep 15 2020 07:30 PM

Grab driver-partners and delivery riders undergo swab testing at the Quezon Memorial Circle on July 30, 2020. George Calvelo, ABS-CBN News file photo

MANILA - The Department of Health (DOH) has been very busy lately explaining why COVID-19 data reporting has been somewhat irregular. Specifically, they’ve been trying to explain why some COVID-19 cases earlier reported as recoveries are now being tagged as active or worse deaths.

This was posted on Sept. 13.

The statement of the DOH lays the blame for these mistakes in the reporting of recoveries, deaths and active cases at the feet of regional epidemiology and surveillance units, local government units, and health facilities. The DOH says these are the reporting entities that “upon further validation, correct their own initially-reported recoveries and re-tag them as deaths.”

The DOH has also stressed the need for complete data in contact tracing as the reason for some of the latest hiccups in data reporting. Here is an IATF order dating Aug. 17, 2020. The order calls on all disease reporting units, the same units mentioned earlier, to ensure specimens for testing are accompanied by the personal information required to start contact tracing. This includes the full name, address and contact details of each subject.

Health Undersecretary Maria Rosario Vergeire says this is why there has been a number of laboratories that have failed to report on their COVID-19 testing results on multiple days this month.

On Sept. 14, the DOH announced that 297 cases previously reported as recovered were tagged erroneously, with 253 of the total actually resulting in deaths and 44 remaining as active COVID-19 cases. As a result, 259 deaths were reported, the highest tally in a single day.

These developments put into question some of the gains the ABS-CBN Data Analytics Team recently reported, the reasons for optimism regarding the Philippines’ fight to contain COVID-19.

That said, we are constrained to look at the data available. As the DOH says, the numbers it puts forth are “the most accurate available.” Even if these numbers are limited by still evolving reporting methodologies, they are all we have to go on.

Let’s look at the latest numbers.

ABS-CBN Data Analytics Team

This chart shows us the data most affected by the inaccurate reporting of recoveries, confirmed COVID-19 deaths in the Philippines. The blue line, representing the 7-day moving average of this measure, can’t give us the complete picture because every week the DOH comes out with so-called "mass recoveries" data, which may or may not contain cases that have been tagged erroneously by disease reporting units. Furthermore, the breakdown shows most of the deaths reported actually happened at an earlier time.

However, with each weekly update, we do get a better picture of total COVID-19 fatalities, thanks to this practice. This at least allows us more insight on how fatal the disease really is in the Philippines. And from this data, reported deaths are on an upward trend. An average of 106 fatalities was reported daily in the past week (Sept. 8 to 14).

ABS-CBN Data Analytics Team

This chart on testing gives us something more. Testing remains elevated, and this is a good sign. The Philippine health sector managed its highest total tests conducted in a single day on September 10 at 43,554. 

Testing is averaging close to 37,000 a day this month, much better compared to the earlier or even middle months of the Philippine quarantine period. While the number of tests has been rising, it seems to have plateaued recently. It can’t be stressed enough, more testing produces more information on the COVID-19 pandemic in the Philippines, giving decision makers more accurate information on which to base their next steps to fight the virus. 

It has been argued that more testing produces more positive cases. This can only be true if there is more local transmission of the virus. 

ABS-CBN Data Analytics Team

The Philippines’ daily positivity rate, a ratio comparing total positive tests versus total individuals tested is one of the best measures to track viral transmission. This ratio naturally goes down if testing is expanded aggressively. The only way for it to go up is for positive cases reported to outpace the increase in testing. The World Health Organization (WHO) says a positivity rate of 5 percent or lower would be optimal, indicating a decline in local transmission. The Philippines is still averaging a positivity rate of more than 10 percent, as shown by the blue line in this chart.

The Philippines remains in an elevated state of COVID-19 transmission. But the trend of the positivity rate is at the very least plateauing, and moving lower compared to July and August. 

This may be a function of the return to modified enhanced community quarantine (MECQ) in Metro Manila and surrounding provinces, instituted between Aug. 4 and Aug. 18. September data however should also reflect the impact of the return to more relaxed quarantine conditions in the same areas. 

ABS-CBN Data Analytics Team

Consider this chart, which shows confirmed COVID-19 cases reported daily, alongside its 7-day moving average shown by the blue line graph. The daily reported totals are once again spiking, hitting a high of nearly 5,000. Remember, the return to tighter quarantine in August was ordered after the health-care sector pleaded with the government for respite for exhausted doctors, nurses and workers from crowded intensive care units (ICU). Furthermore, the DOH also warned us last week that reported COVID-19 cases may be "irregularly high" as more reporting units catch up new methodologies for data updates.

ABS-CBN Data Analytics Team

This chart shows the occupancy rate of ICU beds dedicated to COVID-19 patients in the National Capital Region (NCR), Calabarzon, and Central Visayas. NCR in particular was in the DOH-designated danger zone of 70 percent in August. It has improved. But NCR, together with Calabarzon, are just 10-percentage points away from reentering the danger zone. Hospitals in Central Visayas meanwhile were in the danger zone in July, but these have since improved drastically since the institution of enhanced community quarantine (ECQ) in Cebu City, the tightest of all lockdowns. The hope is for NCR and Calabarzon to retain their gains after reverting to lighter lockdowns, exactly the way Central Visayas did. 

The latest disclosures of the health department have the unavoidable effect of weakening confidence in the COVID-19 data bulletins posted each day. But we cannot stop monitoring these numbers just because of hiccups in data gathering. Testing is improving, positivity rate has somewhat plateaued, but daily cases reported are up. The only real conclusion we can come up with right now is COVID-19 remains a clear and present threat to the Philippines. There is no reason for complacency.