Expert sees ‘no harm’ in mixing COVID-19 vaccine doses

FILE PHOTO: A woman holds a small bottle labelled with a “Coronavirus COVID-19 Vaccine” sticker and a medical syringe in this illustration taken October 30, 2020. REUTERS/Dado Ruvic/File Photo

MANILA, Philippines — While it remains to be investigated, there is no harm in mixing vaccines or inoculating a person with two different vaccine brands, an expert said Saturday.

Dr. Lulu Bravo, executive director of the Philippine Foundation for Vaccination, said that mixing vaccines is already being practiced especially when the supplies are scarce.

“It remains to be investigated, but there is no harm. In general, maraming mga nangyayaring ganyan, even before. Hindi lang dito maaaring mangyari sa COVID. Kasi kaming mga pediatrician, doon sa mga bata nangyayari yan,” Bravo said during the Laging Handa briefing.

“Walang kumpanya pa na gumagawa ng ganitong pagaaral na imi-mix mo yung bakuna nila sa iba. That is never done before but now with the pandemic, sinabi mo kanina, narinig ko na mayroon nang mga kumpanya, even our Chinese companies tsaka even yung ibang kumpanya, nagiisip na talaga na pag kulang yung bakuna at wala kang ibang magamit for the second dose, posible talaga na gagawa ka ng ibang brand or ibang bakuna,” she added.

Bravo, however, noted that mixing vaccines could change its efficacy level. Despite this, the expert speculated that vaccines with the same makeup could have a similar efficacy even if they are mixed.

“May possibility talaga na mag-iiba [ang efficacy] kung ang ginamit mo ay ibang bakuna. Sabi nga natin, posibleng magdagdag ka ng efficacy or tumaas, posible rin na bumaba o posibleng the same. It remains to be seen,” Bravo said.

“Pero hindi masama, hindi makakasama kung makapag-iba ka or mabago. Nagyon, we usually think na kung magkamukha yung bakuna, baka pareho sila ng efficacy,” she added.

Citing insufficient data, Health Secretary Francisco Duque III earlier said that for now, he does not advocate “mixed-use vaccines” or giving a person a second shot using a vaccine made by a different drugmaker.

“I do not advocate for this as of yet, there is no sufficient data to force the claim that a mixed vaccine policy works,” Duque said.

“Kapag nagbigay ka ng ibang bakuna sa first dose, halimbawa Sinovac, then second dose mo AstraZeneca, pag nagkaroon ng problema, adverse event following immunization, serious side effect, paano mo ituturo ‘yung siya ba ay first dose, Sinovac, or second dose, AstraZeneca?” Duque added, by way of an example.

Bravo said the second dose of different brand of vaccine can be given after 12 weeks to see the adverse events from the first dose.