Heterologous booster generates more antibodies for Sinovac recipients –preprint study

Though all vaccines are effective, a heterologous booster vaccination or a booster using a different vaccine brand would generate more antibodies for individuals who were vaccinated with Sinovac for their primary series, according to a study abroad.

According to infectious disease expert Dr. Rontgene Solante, the preprint study from the Lancet, which still has to be formally published and peer-reviewed, the subjects in the study were individuals boosted with AstraZeneca, Pfizer, Janssen, and Sinovac in Brazil.

Though antibody levels were low prior to the booster vaccination, results show that the levels significantly rose 28 days after the third dose.

“After booster was given 28 days after, given the third dose, all groups had a substantial rise in the IgG antibody levels. That means there was a response to the booster doses that were given,” Solante said.

He added that the geometric fold-rise or the measure of the antibody was recorded at 90 for AstraZeneca, 152 for Pfizer, 77 for Janssen, and then 12 for Sinovac days after the booster shot.

“So all of these vaccines elicited a substantial rise in the IgG level. All heterologous regimes had spike antibody response at day 28 that were superior to the homologous booster response,” Solante said.

“Ang ibig sabihin nito, ‘yung nakatanggap ng Astra, Janssen, and Pfizer vaccine, mas mataas ‘yung antibody level nila kumpara doon sa nakatanggap ng Sinovac as a third dose. So that’s the comparison,” he added.

(This means that those who received Astra, Janssen, and Pfizer had higher antibody levels compared to those who received Sinovac as a third dose.)

According to Dr. Mario Jiz of the Research Institute for Tropical Medicine, the antibody level in those boosted with AstraZeneca increased from 3,700 to 335,212 28 days to a month after the booster dose.

“There is an 89 fold increase in the antibody levels. Ganoon po kalakas ang ating booster shots. So there is an almost 90 fold increase in the antibody levels when we administer the AstraZeneca vaccine,” he said.

Meanwhile, the antibody level of those who received Pfizer increased from 4,000 to 674,000.

“So if you have the chance to have a booster, regardless po kung AstraZeneca yan or Pfizer, those are really good options to provide enhanced antibody immunity,” Jiz said.

Further, Solante said that there were no life-threatening or very serious adverse events related to boosting.

“I think the conclusion here is the use of booster doses with any of these platforms only indicated that they are safe and they can also induce protection,” he said.

The National Vaccine Operations Cluster previously said that heterologous vaccination is more effective and is recommended for the immunocompromised.

However, it said that recipients of homologous doses may experience fewer adverse events.

For her part, Health Undersecretary Maria Rosario Vergeire stressed that all vaccines were effective and safe.

“Pinapaalalahan po namin ang lahat na hindi importante ang brand ng bakuna na inyong matatanggap para sa inyong booster dose,” Vergeire said in a media briefing.

(We remind everybody that it is not important what brand of vaccine you will receive for your booster dose.)

“Ang lahat ng bakuna na nabigyan ng emergency use authority ay pinatunayan ng datos bilang ligtas at epektibo sa paghahatid ng proteksyon laban sa malubhang sakit dulot ng COVID-19,” she added.

(All vaccines given emergency use authority are proven by data to be safe and effective in protecting against severe COVID-19.)

— DVM, GMA News