MANILA (2nd UPDATE) - The Philippines began the vaccination of children ages 5 to 11 against COVID-19 in Metro Manila on Monday after a few days of delay due to "logistical challenges."

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The rollout will later be expanded nationwide as government aims to inoculate some 15 million children in the said age group, the Department of Health earlier said.

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"This is an important step of the government because we know children, especially 5 to 11 years old, are also as vulnerable as the elderly," said Dr. Rontgene Solante, head of the Adult Infectious Diseases and Tropical Medicine unit of the San Lazaro Hospital.

Children and their parents must pre-register with local governments and both must bring valid IDs with pictures, according to DOH guidelines. Only children with preexisting medical condition need to present a medical certificate from their doctors while others will be assessed prior to vaccination.

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Government will administer 10 micrograms of Pfizer's reformulated vaccine for children ages 5 to 11, which has an orange cap to be differentiated from the ones used on adults or those with a purple or gray cap.

"Safe po, ligtas po ang bakuna ng 5 to 11 years old. Kailangan po nila ito dahil wala silang bakuna. At kung patuloy tataas ang mga kaso sa ibang lugar, kailangan po protektado din po sila," Health Undersecretary Maria Rosario Vergeire earlier said.

(Our vaccine for 5 to 11 years old is safe. They need it because they haven't been vaccinated yet. And if cases continue to rise especially in other areas, they need to be protected.)

Children will be monitored for 30 minutes if they have experienced allergic reactions, and 15 minutes if they have not experienced any.

The most common minor adverse reactions that children experience are dizziness, injection site pain, pyrexia, headache, and increased blood pressure, according to Dr. Mary Ann Bunyi, president of the Pediatric Infectious Disease Society of the Philippines.

The country has recorded 2 cases of myocarditis and 1 case of pericarditis from which the children have recovered, Bunyi said.

"These patients have all recovered from these conditions. The causality of these medical illnesses is still being investigated and still needs to be established," she earlier said.

The Philippines has so far fully vaccinated 6.28 million children aged 12 to 17 as of Jan. 23, according to DOH data that Bunyi presented.

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Some 160,000 children, including 100,000 in Metro Manila, have so far registered for vaccination, Health Undersecretary Myrna Cabotaje earlier said.

As of 9 a.m., more than 40 children out of a registered 300 have been vaccinated at the National Children's Hospital, according to its medical center chief Moriel Creencia.

At least 2 parents last week asked a Quezon City court to stop the inoculation against COVID-19 of children aged 5 to 11.

"Baka hindi lang nila alam gaano kaimportante ang bakuna sa mga bata, and nakikita na natin na ang mga bata ay isa sa mga target ng COVID na ‘pag nagka-COVID ka, napaka-severe ng infection, napaka-severe ang course," Solante said of the petition in a public briefing.

(Perhaps they just do not know how important the vaccine is to children, and we have seen that children are one of the targets of COVID, where if you catch COVID, the infection is severe, the course is very severe.)

"Siguro (maybe) we need to educate, we need to inform them [of] the importance of vaccination," he added.

--Report from Gillan Ropero, Wena Cos, Jamaine Punzalan and Anna Cerezo, ABS-CBN News

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