SINGAPORE – Although health authorities here expect Pfizer-BioNTech and Moderna to provide protection against coronavirus for up to 18 months, vaccinated individuals will eventually need an auxiliary dose to protect themselves from new variants of COVID-19.
“Although vaccination provides a clear protective benefit to anyone who may be exposed to COVID-19 infection, vaccination is not 100 percent protective. (I) after (18 months), it is still a relatively uncertain situation,” said service director Kenneth Maka on the virtual press conference on Thursday (April 22nd).
He added that Singapore, like other countries, has studied the possibility of an increased dose, in addition to the two doses of vaccine given to individuals.
Associate Professor Mack pointed to two events that may determine the need for a third dose. First, the “gradual weakening of immune protection” that can occur in vaccinated individuals, as seen in those re-infected with COVID-19.
And second, viral variants of concern, such as the UK, Indian and South African variants that have emerged around the world in recent months and that may be resistant to current vaccines. As of Tuesday, a total of 350 local and imported cases of various variants of COVID-19 have been detected in Singapore.
“And if that were the case, it might be that we need doses of the booster vaccine to boost the immunity we already have from previous vaccinations and to give us extra protection, especially against these worrying variants.”
The Pfizer-BioNTech and Modern COVID-19 vaccines are the only ones approved for use here.
Preliminary studies show that vaccines from AstraZeneca and Chinese Sinovac are partially effective against the Brazilian variant. The Pfizer-BioNTech vaccine, one of two approved here, has also been shown to be effective against strains, but studies show that it is less effective against the South African variant.
Two new Modern vaccines designed to protect against the South African and Brazilian variants have given promising results to those tested on mice, according to recent data. The original Moderna vaccine is approved for use in Singapore.
As of last week, about 1.36 million individuals in Singapore have received at least one dose of Pfizer-BioNTech or Moderna, and more than 849,700 of them have received another dose of the same vaccine and completed the full vaccination regimen.
An analysis of the number of applications of each type of vaccine is not publicly available here.
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