KUALA LUMPUR, Oct 25 — Singapore’s health regulators have authorised a bivalent formulation of Pfizer-BioNTech’s Covid-19 vaccine – which protects against the original SARS-CoV-2 strain and the Omicron variant – as a booster for individuals aged 12 years and older.
The Health Sciences Authority (HSA) of Singapore announced today that it granted Pandemic Special Access Route (PSAR) interim authorisation for the Comirnaty Bivalent (Original/Omicron BA.4/5) Covid-19 vaccine by Pfizer on October 11.
The vaccine is an updated version of the original Pfizer vaccine and has been approved for use as a booster jab for individuals 12 years and above who received their Covid-19 primary series vaccination.
Pfizer’s bivalent vaccine contains two mRNA components: 15 micrograms targeting the original SARS-CoV-2 strain, which is present in Pfizer’s original Comirnaty vaccine, and 15 micrograms targeting the Omicron BA.4 and BA.5 variants.
“As the clinical study by Pfizer for Comirnaty bivalent (Original/Omicron BA.4/5) vaccine is still under way, the assessment of the efficacy of the vaccine was based primarily on an earlier Phase 3 clinical study conducted in individuals aged above 55 years with Comirnaty bivalent (Original/Omicron BA.1) vaccine,” HSA said in a statement.
“HSA considers such data as relevant taking into account that these Omicron subvariants are closely related. The study showed that the bivalent vaccine elicited a stronger immune response against the targeted Omicron BA.1 subvariant, while still maintaining an adequate response against the original SARS-CoV-2 strain.
“This indicates that bivalent vaccines provide a broader immunity and better protection against the SARS-CoV-2 virus.”
HSA also cited an ongoing Phase 2/3 study of the bivalent (original/ Omicron BA.4/5) vaccine, where a preliminary analysis in a subset of 80 participants aged 18 years and above showed consistent trends of higher immune responses against the Omicron BA.4/5 subvariant and continued response against the original SARS-CoV-2 strain.
“Additional results are expected as the study progresses and continues to generate more data.”
Singapore’s health regulators expect the bivalent vaccine to trigger comparable or better immune responses in adolescents than older adults, as the younger population generally develops a higher immune response compared to older people.
“As the original Comirnaty vaccine has been approved across these age groups, there is a large amount of real-world data from local and overseas surveillance studies supporting its effectiveness and safety. It is reasonable to conclude that the variant-updated bivalent vaccines will retain similar effectiveness and safety profiles,” HSA added.
HSA also said the safety profile for Pfizer’s bivalent vaccine was consistent with what is known for the original vaccine that has a large amount of available safety data. Adverse events were mostly mild-to-moderate, such as injection site pain and/or tenderness, fatigue, headache and muscle pain.
“The authorisation of Comirnaty Bivalent (Original/Omicron BA.4/5) is based on the totality of available evidence, including Pfizer’s non-clinical studies, clinical trials with different variant-updated vaccines, and the quality and manufacturing processes.”
Pfizer Inc and BioNTech SE said in a joint statement today that their previous October 12 announcement of early data from a Phase 2/3 clinical trial on their bivalent (original/Omicron BA.4/5) vaccine – as cited by HSA – showed a “substantial” increase in Omicron BA.4/5 neutralising antibody response above pre-booster levels, seven days after administration.
Similar responses were seen across individuals aged 18 to 55 years old and those older than 55, based on 40 participants in each age group.
Pfizer-BioNTech also said that their original vaccine elicited more limited increases in neutralising antibody levels against the Omicron BA.4/BA.5 variants, compared to the bivalent vaccine, for people aged above 55.
“Additional data measuring responses at one-month post-administration of the Omicron BA.4/BA.5 bivalent vaccine booster are expected in the coming weeks,” said the pharmaceutical companies.
“It is important to stay vigilant against the Covid-19 virus, and vaccines remain our first line of defense. We believe that developing variant-based vaccines, like this one, is essential in ensuring children and adults maintain a high level of protection,” said Pfizer Singapore country manager Erika Pagani in the statement by Pfizer-BioNTech.
“The PSAR authorization by HSA marks a major milestone in the ongoing fight against Covid-19 and we are working closely with the Singapore government to make the vaccine available in a timely manner.”
Channel News Asia reported Singapore’s Health Minister Ong Ye Kung as saying last Sunday that the number of Covid cases in Singapore has peaked and is beginning to descend. Singapore is in the middle of a Covid wave caused by the XBB variant, or BA.2.10.
According to Channel News Asia, about one in five daily coronavirus cases in Singapore now are reinfections.
Ong reportedly recommended that senior citizens take Moderna’s new bivalent vaccine. Singapore’s Ministry of Health previously stated that the bivalent vaccine would be offered to health care workers in the public and private sectors starting from October 25.