OCTA Research Group urged the government to evaluate the surge capacity of densely populated Metro Manila as the threat of coronavirus disease (COVID-19) outbreak will remain present while waiting for the arrival of vaccines.

"Preparing for a surge requires knowledge of the current surge capacities for contact tracing, testing, and hospitalization. Anticipating the level of the surge is important in order to scale up these capacities," OCTA said in a special report released on Tuesday, April 27.

"Without preparation, the only recourse once the surge exceeds these capacities is to lockdown, in order to prevent a further overwhelming of hospitals," it added.

OCTA said that preparing for a possible outbreak requires an honest evaluation of the surge capacity in four important criteria--contact tracing, testing, health care system, and isolation and quarantine facilities.

Based on available data, the surge capacity in the National Capital Region (NCR) for testing is 3,000 new COVID-19 cases per day, and the surge capacity for hospitalization is 2,688 new COVID-19 cases per day.

Estimating the surge capacity for contact tracing requires more data but a current estimate is 1,500 new COVID-19 cases per day.

"Suppose that the NCR local governments are able to contact trace 15,000 fresh contacts per day. In January, when the daily new cases in NCR was around 500, this would mean a contact tracing ratio of 1:30," OCTA cited.

However, during the surge in March 2021, the NCR averaged around 5,000 new cases per day. Given the same contact tracing capacity, this gives a ratio of only 1:3.

"Three contacts made per day for each identified infected individual is unfortunately not very efficient," OCTA pointed out.

"These three contacts are usually just the people in the same household as the infected. Contact tracing is very important in the early identification of those who are exposed to the virus because reducing viral transmissions by infected individuals will reduce the observed reproduction number," it added.

OCTA said that with 15,000 contacts per day, the surge capacity for contact tracing is around 1,500 new COVID-19 cases per day, for a decent 1:10 ratio.

"If the national government can bolster contact tracing to 30,000, then this will increase the surge capacity to 3,000 new cases per day," it said.

The surge capacity for testing is based on an acceptable positivity rate and the ideal positivity rate recommended by the World Health Organization is less than 5 percent.

"At this rate, testing is sufficient and will identify most of those who have contracted the virus," OCTA said,

In January 2021, the NCR Plus had an average of 15,000 tests per day.

At an average of 600 new Covid-19 cases per day in NCR Plus, this translates to a positivity rate of 4 percent.

During the March 2021 surge, daily testing capacity increased to almost 30,000.

"A positivity rate of 10 percent would be maintained if the number of new cases reached 3,000 per day. Thus, the surge capacity of testing is 3,000 cases per day in the NCR," it said.

"A surge to 7,500 new cases per day (in NCR Plus) increased the positivity rate to 25 percent. To accommodate a surge to 7,500 daily cases, testing capacity must be increased to 75,000 tests per day," it added.

Based on available data, there is a sufficient number of isolation facilities in the NCR, as the Department of Public Works and Highways scaled up the number of isolation facilities.

As such, surge capacities for isolation and quarantine in the NCR were not studied by OCTA.