The Department of Health (DOH) said Tuesday the optional wearing of face masks may be among the factors that caused coronavirus disease (COVID-19) cases to rise.

In a press conference, DOH Officer-in-Charge Maria Rosario Vergeire said: ''It is not just one factor, particularly the optional masking policy, that has caused the increase in cases. It has several components that cause people to get infected... But it is possible that the optional masking has started to become one of the factors. ''

"First factor is the inherent characteristics of people like being elderly, immunocompromised, has comorbidities, young. Second factor is the virus' characteristics being more transmissible. Third factor is the behavior of people like increased mobility, non wearing of face masks, opening of more sectors," she added.

The DOH reported last Monday that average daily COVID-19 cases for September 19 to 25 has increased by 22 percent from the previous week.

"It is important that the severe and critical cases do not surge and that our hospital beds will not be overwhelmed," said Vergeire.

If not, she said the DOH will push that the mandatory face mask policy must return.

The Palace announced on September 12 that face masks wearing will be optional in open spaces and non-crowded outdoor areas with good ventilation.