MANILA— The NCR Plus and the Visayas have seen an increase in COVID-19 cases, the Department of Health said Friday, as it noted the country remains at low risk for the spread of the disease.

This, just as health officials confirmed this week local transmission of the highly contagious Delta variant, prompting hospitals and local government units to prepare for a possible fresh surge in COVID-19 cases.

Health Undersecretary Maria Rosario Vergeire, in a press briefing, said the presence of more transmissible variants could be "correlated" to the case spikes.

"Nationally, risk classification remains to be at low risk with an average daily attack rate continuing to decrease in the recent week," she told reporters. "However, more regions are experiencing a trend reversal to positive 2-week growth rate."

From July 16 to 22, the country recorded 5,666 coronavirus infections, an increase of 626 cases compared to the previous week. A total of over 1.5 million cases have been logged in the Philippines.

"After a slow decline in the past weeks, the case trend in the NCR Plus areas is showing an increase in the recent week," she said.

"Visayas is also showing an upward trend in the number of cases while Mindanao has a slight increase this week, and the case trend in the rest of Luzon is plateauing," she added.

Vergeire said NCR Plus, composed of Metro Manila and the provinces of Bulacan, Cavite, Laguna and Rizal, showed signs of case increase.

The capital region logged 797 infections from July 16 to 22, an increase of 179 cases. But it is nowhere near its peak from March 29 to April 4, which had 5,534 cases.

Rising COVID-19 cases were also observed in Bulacan, Cavite, Laguna and Rizal in the same period, Vergeire said. Cavite (259) and Bulacan (172) had the fastest increase.

"There is a need to identify the causes for this increase in cases in these local governments to preserve the gains achieved in the past 2 months," she added.

In the rest of Luzon, an upward trend of cases was also noticed in Cagayan Valley, Central Luzon and Calabarzon, while Bicol Region was on a downward trend.

Vergeire said Ilocos Region, Mimaropa and the Cordillera Administrative Region showed a plateauing trend in cases.

In the Visayas, Central Visayas reported a "steep rise" in cases, with 577 new infections recorded from July 16 to 22, the health official said. The region logged 422 cases in the previous week.

She said COVID-19 cases in Eastern Visayas (177) were declining while the case trend in Western Visayas (644) was plateauing.

In the south, Northern Mindanao reported a "sharp increase" in COVID-19 cases, with 277 new infections tallied over the same period. It only had 206 cases in the past week.

Caraga (136) and the Bangsamoro Autonomous Region in Muslim Mindanao (37) also showed an uptick in virus infections, Vergeire said.

Meanwhile, a downward trend was observed in the Zamboanga Peninsula (78) and Davao Region (414) while the case trend in Soccsksargen (214) was plateauing.

"We need to continually strengthen border control versus continuous travel ban given that the list of these countries with variants of concern and case spikes grow longer everday," Vergeire said.

• DOH confirms local transmission of COVID-19 Delta variant

The DOH on Thursday confirmed local transmission of the highly contagious Delta variant in the country. The variant originated from India and caused a catastrophic spread of the virus there.

So far, there are 47 cases of the Delta variant recorded in the Philippines. The tally includes 36 recoveries, 3 fatalities and 8 active cases.

The latest COVID-19 outbreaks in parts of Asia are linked to the Delta variant.