SINGAPORE - About 550,000 individuals have been invited to take Covid-19 vaccine booster jabs, Health Minister Ong Ye Kung said on Monday (Oct 4).

Of these, 350,000 have done so or booked an appointment. Some 240,000 people have completed their jabs, he told Parliament.

Responding to questions from MPs, he said that individuals eligible for boosters will include those aged 50 and above and all who are immunocompromised.

The Expert Committee continues to review international data to assess the efficacy and safety of booster shots for younger groups, as well as those exposed to higher-risk environments, such as healthcare and front-line workers, Mr Ong said.

He added: "In time, we will also be inviting eligible individuals who have taken the Sinovac or SinoPharm vaccine... to take their mRNA booster shots. However, most of them are not due yet."

Mr Ong said vaccination remains key to the nation's battle against Covid-19.

Those fully vaccinated with the Pfizer-BioNTech or Moderna vaccines are about 40 per cent protected against infection from the Delta variant, he said.

"Nevertheless, both vaccines remain very effective in protecting against severe illnesses from Covid-19 infections," Mr Ong added.

As for those who have received the Sinovac vaccine, "meaningful data" on its effectiveness is not yet available as only a small number of people - less than 2 per cent of the population - have received this shot.

Correction note: An earlier version of this story reported that 0.5 per cent of those who have been fully vaccinated with the Pfizer-BioNTech and Moderna vaccines have been infected with Covid-19. Mr Ong did not say this in Parliament. We are sorry for the error.