MANILA -- The Department of Health said Thursday it was working to bring back public trust in the government's vaccination program, after immunization coverage last year fell in the aftermath of a scrapped anti-dengue campaign.

From at least 70 percent in the last few years, immunization coverage in 2018 slid to 40 percent, said Health Undersecretary Eric Domingo.

In December last year, the government recalled the anti-dengue vaccine Dengvaxia after its manufacturer, France's Sanofi-Pasteur, said it could cause severe symptoms if given to those who have not had the mosquito-borne disease.

"All of the vaccines were affected. Nothing was spared. Even non-vaccine programs like de-worming," Domingo told ANC.

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An information drive is underway to educate the public on the importance of vaccines. While immunization in some regions are picking up, the DOH is still having difficulty in Metro Manila, he said.

"People in Metro Manila are very exposed to the news and they have very strong opinion with regards to that. That's one big challenge for us. We just have to try harder," he said.

The Senate held several nationally televised hearings on Dengvaxia, which was given to some 830,000 school children during the term of former president Benigno "Noynoy" Aquino III.

Lawmakers said Aquino and his former secretaries "should be held criminally liable" for the program that was done with "undue haste."

Several cases have been filed over the deaths of some who were injected with Dengvaxia, but it has not been established whether the fatalities were caused by the vaccine.