(GMA News) The highly transmissible COVID-19 delta variant may have already spread in the Philippines given the “serious surge” in new cases being reported, independent group OCTA Research warned Sunday.

According to OCTA Research Fellow Dr. Guido David, the numbers indicate that there may already be a lot of individuals who have contracted the delta variant through local transmission.

“Hindi naman dadami ng ganyan na lahat ‘yan galing sa ibang bansa. Ibig sabihin, talagang… meron na at marami na,” he said in a report on GMA’s “24 Oras Weekend” on Sunday.

(It will not surge that much if it was only coming from overseas. This means that it is here and that there are a lot of infections.)

Based on the data from the Department of Health (DOH), there were 1,700 new confirmed cases in Metro Manila on Saturday, July 31, the highest since May 10 when the National Capital Region was placed under the enhanced community quarantine.

“May nakausap kaming mga local government, may isang household, clustering. 18 na tao sa isang household, nahawaan lahat. ‘Yung mga ganyan kabilis, malamang, baka Delta variant ‘yan,” said David.

(We talked to local governments, there was a household that was clustered with 18 individuals who were all infected. That fast of a spread is most likely the delta variant.)

OCTA Research has classified 13 areas as high-risk: Caloocan, Las Pi?as, Makati, Malabon, Marikina, Muntinlupa, Navotas, Para?aque, Pasig, Pateros, Quezon City, San Juan, and Valenzuela.

The group warned that the occupancy rate of intensive care units could rise to as much as 70% in the next three weeks if there are no changes in the quarantine restrictions.

The reproduction number has also risen to 1.52, versus 1.29 earlier in July.