Covid bivalent vaccine shows rapidly declining effectiveness against XBB strain
The effectiveness of bivalent Covid-19 vaccines is likely to decline rapidly as the XBB variant continues to spread, Chulalongkorn University's Faculty of Medicine Associate Professor Dr Thira Woratanarat, posted on facebook today.
The news comes on the heels of Thursday’s meeting between the US Food and Drugs Administration (FDA) and the Vaccines and Related Biological Products Advisory Committee held to discuss the findings of an ongoing study.
While the Bivalent vaccine, which utilises the BA.5 strain, provides good immune response and protection during outbreaks of the BA.5 and BQ.1 strains, its effectiveness decreases rapidly, especially during the XBB variant outbreak.
XBB is a subvariant resulting from the recombination of the BA.2.10.1 and BA.2.75 strains, and it continues to evolve continuously.
Results of the current study clearly indicate that using a vaccine specifically targeting the XBB strain will significantly boost immunity against the XBB.1.5 and XBB.1.16 strains, with a higher immune response against XBB.1.5 compared to XBB.1.16.
The plan is to introduce a monovalent vaccine specifically targeting the XBB strain for the general population starting this autumn, without using vaccines that target the original strains.
For Thailand, where the infection rate remains high, it is important to take the necessary precautions, including the wearing of masks and good hand hygiene to reduce the Covid infection risk.
