Published Siriraj Clinical Research Center (SICRES) has just revealed the study result on pVNT50 (50% pseudovirus neutralization titer) against the Omicron variant.
* All booster doses are 12 weeks following the primary series;
** GMTs = geometric mean 50% pseudovirus neutralizing titers
2-dose primary series Sinovac + booster vaccine Oxford/AstraZeneca = 170 GMT
2-dose primary series Sinovac + booster vaccine (half dose) Pfizer = 551 GMT
2-dose primary series Sinovac + booster vaccine (full dose) Pfizer = 543 GMT
2-dose primary series Oxford/AstraZeneca + booster vaccine Oxford/AstraZeneca = 3 GMT
2-dose primary series Oxford/AstraZeneca + booster vaccine (half dose) Pfizer = 232 GMT
2-dose primary series Oxford/AstraZeneca + booster vaccine (full dose) Pfizer = 521 GMT
Primary series: Sinovac + Oxford/AstraZeneca + booster vaccine (half dose) Pfizer = 204 GMT
Primary series: Sinovac + Oxford/AstraZeneca + booster vaccine (full dose) Pfizer = 150 GMT
Conclusion These findings imply that after two jabs, a booster dosage is required to elicit a significant antibody response against Omicron-mediated COVID-19. The m-RNA vaccine (Pfizer) either half dose or full dose after many formulas of vaccinations shows promising results towards the opposition to Omicron strain. After two doses of Oxford/AstraZeneca, a booster dose of m-RNA (Pfizer) vaccination is recommended.
