Pfizer Covid-19 vaccine approved for children aged 6 months to 4 years
Pfizer's Comirnaty Covid-19 vaccine was on Thursday authorised for use on children aged six months to four years old.
In a statement, the Health Sciences Authority (HSA) said it had carefully considered the clinical data and assessed that the benefits outweighed the risks in administering the Comirnaty vaccine in children in this age group.
The vaccination regimen for the primary series in this age group will consist of three 3-microgram doses - the first two to be administered three weeks apart, followed by a third dose to be administered at least eight weeks after the second dose, said the HSA.
But it added: "Official vaccination recommendations on the use of this vaccine will be issued by the Expert Committee on Covid-19 Vaccination and the Ministry of Health when ready."
The authority also said that it consulted experts from its Medicines Advisory Committee and Panel of Infectious Diseases Experts in making the decision.
This is the second vaccine authorised for use in Singapore by HSA for children aged six months to four years old, after the Spikevax vaccine from Moderna.
The Spikevax vaccine was authorised for use on children aged six months to 17 years old on Aug 24.
As for the Pfizer vaccine, the authority said clinical data it considered included an ongoing Phase 2/3 study conducted by Pfizer, involving about 1,800 participants aged 6 months through 4 years.
"The results showed that the immune response in young children with a three-dose primary series was comparable to that in adults aged 16 to 25 years who received two higher doses of 30 micrograms as the primary series vaccine.
"Hence, it can be inferred that three doses of the vaccine may provide a similar level of protection in young children as that of two doses in adults."
The HSA also said that local real-world data in children aged 5 to 11 years has shown that vaccine effectiveness against the Omicron subvariants was estimated to be around 40 per cent for symptomatic disease and remained high at more than 80 per cent for protection against Covid-19-related hospitalisations for children receiving two doses of Pfizer vaccines.
"Hence, it could reasonably be expected that the vaccine would similarly protect younger children aged 6 months through 4 years from severe outcomes of Covid-19 such as multisystem inflammatory syndrome (MIS-C) and other potential complications.
"There was also preliminary data from a secondary analysis of Covid-19 cases in the clinical study, which suggested that the vaccine efficacy was estimated to be around 73 per cent."
But the authority added that this evidence is limited and should be interpreted with caution.
It also said safety data from the clinical studies also showed that adverse events in young children were similar to those reported in adults.
The adverse events were mild-to moderate and commonly reported with childhood vaccination, such as injection site pain, fever, fatigue and headache.
The HSA said these reactions are associated with vaccinations in general and expected as part of the body's natural response to build immunity against Covid-19.
"They usually resolve on their own within a few days."
However, it added that while there were no cases of serious adverse events such as myocarditis or pericarditis, which refer to inflammation of the heart muscle, reported in the clinical study with the Comirnaty vaccine, it recommends that caregivers of young children should monitor for signs and symptoms of myocarditis such as chest pains and breathing difficulties, as well as take precautions to minimise rigorous physical activity following vaccination.
"HSA will continue to actively monitor the safety of the vaccine and require Pfizer to submit data from the on-going clinical study to ensure that the benefits of the vaccine continue to outweigh the risks."