SINGAPORE - Vaccination centres here were once again a hive of activity on Friday, the first day that Moderna's updated Spikevax vaccine is being offered here.

Seniors and people planning to travel soon made up the majority of those who turned up at the nine joint testing and vaccination centres (JTVC) for the new jabs.

More than 50 people, mostly seniors, were waiting to get the bivalent vaccine jab when The Straits Times went to the Kaki Bukit JTVC in the morning.

The centre began filling with more people at about 11am, but the queue moved briskly.

Some in the queue said they wanted to get the bivalent vaccine as it targets two variants - the original strain and the Omicron variant - thereby conferring better protection. For others, it was for greater peace of mind, given the rising infection numbers due to the XBB Omicron sub-variant.

The Jurong East and Ang Mo Kio JTVCs were crowded at lunchtime, with the waiting time stretching to about half an hour.

Ms Sally Tan, 58, a director in the education sector, brought her 87-year-old mother along to get vaccinated together at Kaki Bukit.

As she is travelling to Europe for work in two weeks' time, Ms Tan said her fourth jab gave her some reassurance.

Mr Nikhil Singh, 46, who works in a bank, took leave to get vaccinated as he is overdue for his booster shot. He had to postpone a trip as his Singpass app reflected that he was unvaccinated.

Client success manager Samuel Tay, 50, said he was getting the bivalent shot to minimise disruptions to his life.

"I've seen colleagues travelling, getting infected and reinfected," he said. "I want to keep the disruption to a minimum."

Vaccination centres at Pasir Ris and Sengkang were quieter when ST visited in the afternoon.

Several people in the queue said they wanted to get the jabs quickly to avoid longer waits, should a new Covid-19 wave prompt more to get their booster shots.

Vaccination centre staff said more seniors dropped by in the morning, and the centres were more crowded than they had been in recent weeks.

Pre-school principal Florence Fok said she had been waiting for the bivalent vaccine to become available, as she planned to get her fourth jab in time for a trip to visit her son, who is working in Tokyo.

"I wanted to quickly get the jab and came down today, since there is no need to make an appointment," said Ms Fok, 57, who was at Sengkang JTVC.

At Pasir Ris, housewife Mariam Osman, 52, said she was prompted to get her second booster after her experience with Covid-19 earlier this year.

"It knocked me out for 11 days," she said. "I want to make sure that if I get it again, the symptoms won't be so bad."

The Moderna bivalent vaccine, which was approved by the Health Sciences Authority in September, has been updated so that it targets the original Sars-CoV-2 strain of the virus as well as the Omicron BA.1 variant.

The Ministry of Health said on Tuesday that clinical trials have showed that it generates greater antibody response and provides better protection against newer Covid-19 variants. Side effects after vaccination were similar for both the bivalent vaccine and the original vaccine, and there were no safety issues observed.

Those who have yet to receive minimum protection (the equivalent of three mRNA doses), or those aged 50 and above and whose last Covid-19 vaccine jab was at least five months ago, can walk into any of the nine JTVCs offering the new vaccine islandwide to get the bivalent shot.

They will not have to make an appointment beforehand.

Individuals can refer to https://www.gowhere.gov.sg/vaccine to locate the nearest JTVC and their operating hours.