More than 3 million doses of Covid-19 vaccines arrived in the Philippines on Thursday, the biggest single-day vaccine delivery since the start of the pandemic.

More than 1 million doses of the Sinovac vaccine arrived in the morning, and 2,279,160 doses of the Pfizer vaccine were due later in the day, according to Palace spokesman Harry Roque Jr.

Roque said the 3.2 million doses are part of the more than 10 million doses the government is expecting this June.

He assured local government units that have run out of vaccines that they will get new stocks soon.

The country now has a stockpile of 10,329,050 doses.

Over 6 million doses have been administered since mass inoculation started on March 1.

On Wednesday, Health Secretary Francisco Duque 3rd admitted that there were not enough doses to jab the 13 million economic frontliners in the National Capital Region and eight key priority hubs.

Duque said the vaccination of 18 million senior citizens and those with comorbidities in the NCR Plus 8 area - made up of Metro Manila, Metro Cebu and Davao City, and the provinces of Bulacan, Cavite, Laguna, Rizal, Pampanga and Batangas - was still ongoing.

The government said 4.63 million individuals have received the first vaccine dose and 1.68 million the second dose as of June 8.

During a briefing Thursday, Department of Science and Technology-Philippine Council for Health Research and Development Executive Director Jaime Montoya said the government was willing to hold clinical trials on Covid vaccines that would be administered to children once the Department of Health and the Inter-Agency Task Force on Emerging Infectious Diseases (IATF-EID) give the green light.

Duque has said the country will not approve the vaccination of children until it has seen the test results in other countries where children have been inoculated against the virus.

Only Pfizer has been given emergency use authority to administer its vaccine to people aged 12 to 17 years. Chinese drugmaker Sinovac has emergency use approval to use its vaccine on children as young as three years old.

Health Undersecretary Maria Rosario Vergeire had ruled out the inoculation of the younger segment of the population because vaccine supplies were still limited.

The People's Vaccine Alliance for Asia, meanwhile, called on governments to support the proposal before the World Trade Organization to waive intellectual property rights for patents of vaccines, medical equipment, diagnostics and therapeutics until the majority of the world's population has been inoculated against Covid-19.

The group also called on big pharmaceutical companies and rich countries to join the Covid-19 Technology Access Pool (C-TAP) initiative by the World Health Organization, a one-stop shop for developers of Covid-19 therapeutics, vaccines, and diagnostics to voluntarily share their IP and data.

Dinah Fuentesfina, co-coordinator of the PVA for Asia, said most countries in the region are seeing their health system collapse under the weight of rising Covid-19 cases and a slow vaccine rollout.

"It is not only an ethical imperative, but it is also a justice imperative... There is an urgent need for people's voices to state more strongly the importance of vaccine equity and in the face of how developed countries are hoarding much more than they need.... the need for civil society to raise more pressure and raise stronger actions is more urgent," Mae Buenaventura of the Asian People's Movement on Debt and Development said.

On Thursday, the country recorded 7,485 new Covid cases, pushing the total to 1.294 million infections.