SINGAPORE - A Pulau Ubin resident was anxious to get his Covid-19 jab, but getting to mainland Singapore - where the vaccines are administered - was not easy for him.

The retiree, who wanted to be known only as Mr Tan, had his right leg amputated last year because of diabetes. The trip would require others to carry him to board a boat at the jetty.

While his 76-year-old wife has no problems going to the mainland, where she recently received both her jabs, Mr Tan, 79, stays put unless he has pressing medical appointments.

Living atop a small hill near the jetty, he does not come into contact with many people other than his wife and National Parks Board (NParks) officers who check in on him - and other older residents on the island - weekly.

On Friday (July 2), spurred by his plight, a team of doctors led by Dr Yan Shi Yuan boarded a bumboat, taking along a vial of Moderna vaccine in an icebox, in Singapore's first civilian offshore vaccination initiative since the coronavirus began in January last year.

There, the team, organised after NParks requested help, gave 10 people their first dose, in an effort that lasted about two hours, bringing the vaccination rate on the island to nearly 90 per cent.

Three of them, including Mr Tan, had mobility issues and were inoculated in their homes. The other seven received theirs at a shelter near the main jetty. They are two residents who joined the nationwide scheme after NParks reached out to them, three domestic workers who work on the island and two employees of a seafood restaurant.

An hour after his dose, a relieved Mr Tan, who was resting on his verandah and playing a game on his mobile phone, said: "It is very good that they brought the vaccine to me because it is so inconvenient otherwise. I now have peace of mind."

To date, most of the approximately 30 people who live on Pulau Ubin have had at least one jab, with the remaining 10 per cent either deciding against it as they do not go out much, or are still unconvinced, according to NParks officers.

Overall, 3.3 million, or 60 per cent of Singaporeans, have received their first dose. The aim is for two-thirds of residents to be fully inoculated by National Day on Aug 9, the Government has said.

Dr Yan, who is director of Edgedale Medical Clinic, said he and the authorities visited Pulau Ubin a few times before Friday to make sure that they could successfully vaccinate the 10 people without the shots expiring.

The availability of Internet access so patients can be e-registered, the ease of evacuation if complications arise and the travel time to Changi Point Ferry Terminal and the subsequent 10-minute boat ride to Pulau Ubin were all considered.

Moderna was chosen over Pfizer-BioNTech as the latter has a six-hour expiry limit after it is drawn from the vaccination centre. In contrast, the Moderna drug just needs to be stored in an icebox kept between 2 deg C and 25 deg C.

The team used a thermometer and a buzzer that alerted them if temperatures got too close to these limits.

"It was important to us not to waste any vaccine. We did not take along an extra vial as each vial is very precious. One Moderna vial can administer 10 doses, so we also made sure that the number of people getting vaccinated matched this," Dr Yan said.

"People living in isolated places need the vaccine too, and it is very crucial that we take it to them. In essence, administering doses here and on the mainland is not much different."

Footfall on Pulau Ubin has picked up since borders were closed, with many Singaporeans seeking it out as a place for leisure amid the pandemic. In November last year, about 25,000 people turned up.

With so many people coming into contact with islanders, it became crucial that those on Pulau Ubin are also protected against Covid-19.

Mr Law Kuing Liak, 75, owner of a provision shop on the island where many visitors stop to rest and drink, said he was getting quite wary about being so close to people congregating in front of his outlet.

He has had multiple back operations since his first 10 years ago, and does not go to the mainland except for medical consultations.

Mr Law said: "I really appreciate what the NParks officers have done for me. My relatives encouraged me to get the dose after they got theirs. And, although I was a little nervous during the jab, I am much less anxious about catching the virus from visitors now."

The team will be back on July 30 to administer the second doses.