There are currently two bivalent COVID-19 vaccines in Singapore offered by the Ministry of Health (MOH) – the bivalent Moderna/Spikevax and the bivalent Pfizer-BioNTech/Comirnaty.
Bivalent vaccines work by stimulating an immune response against two viruses.
Both bivalent COVID-19 vaccines target the Omicron variant in addition to the original COVID-19 virus. It can therefore provide better protection against newer COVID-19 variants.
The Omicron variant targeted by the bivalent Moderna/Spikevax is the BA.1 subvariant, while the bivalent Pfizer-BioNTech/Comirnaty vaccine targets the BA.4/5 subvariant.
There is currently no evidence that a specific bivalent vaccine is better than the other in terms of protection against future variants. As such, either can be used as a booster vaccination.