SINGAPORE - Retiree Tan Kian Boon, 69, is more afraid of dying from potential complications of the Covid-19 vaccine than of catching the coronavirus itself.

He thinks it is unlikely he would get infected as he wears a mask when he goes out. Though he is not vaccinated, he is considering the Sinovac vaccine, which he feels is more reliable since it was developed using traditional methods.

The Pfizer-BioNTech and Moderna vaccines that are currently available under Singapore's national vaccination programme are based on mRNA technology, which has not been used in vaccines before now.

Mr Tan said in Mandarin: "We don't actually need a vaccine to defeat the virus. Our bodies can recover by themselves. We just need to exercise, get some sun and adjust our diets."

Mr Peh Leong Kok, too, is afraid of dying after getting vaccinated.

The retired restaurant worker remembers reading that a senior citizen died after he was vaccinated, though he does not remember any other detail.

Also, Mr Peh, 82, had surgery for a chronic digestive disease a few years ago, and suffers from high blood pressure and other ailments, so he is afraid of running into more problems because of the vaccine.

Fear of complications or side effects from the vaccine is the key reason stopping seniors from getting vaccinated, The Straits Times found, in speaking to 35 seniors on Friday (June 25). Of those, seven were yet to be vaccinated.

On Thursday, Health Minister Ong Ye Kung said about 75 per cent of people aged 60 and older had received at least one dose of the vaccine, but that this was "not enough".

The task force tackling the pandemic said seniors should protect themselves through vaccination as they are most vulnerable to the disease and face a higher risk of severe illness. Their risk will increase once safe distancing measures are gradually eased, said Trade and Industry Minister Gan Kim Yong.

Seniors who have been vaccinated include Mr Ranjen Nadarajah, 65, who runs a market stall. He said he had the jab because it makes it safer for him and those around him.

But there are other seniors refraining from doing the same.

Mr Sunny Tan, 74, said there was no need to get vaccinated as the Government is doing such a good job of managing the pandemic that he does not worry about catching the virus.

A woman who wanted to be known only as Madam Toh, 65, is the sole caregiver to her 103-year-old mother. She has not made an appointment for her mother, who she said is "so old already". She, too, has not been vaccinated, although she wants to.

Mr Edward Tang, who oversees two senior activity centres run by Care Corner Singapore, said news of deaths after vaccination, like those in Norway, has spooked some seniors.

In January, more than 30 people in Norway aged 75 and older died after getting vaccinated. But all of them were reported to have been already seriously ill prior to getting their shots.

The Norwegian health authorities have said there is no evidence of a direct link between the deaths and the Pfizer-BioNTech vaccine they received.

Mr Tang added that some seniors are also afraid of the usual side effects associated with the vaccine, such as fever, giddiness and a sore arm. "They want to avoid unnecessary pain and discomfort," he said.

The Silver Generation Office, the outreach arm of the Agency for Integrated Care (AIC), has been working with the People's Association to explain to seniors the benefits of the vaccine, through phone calls and house visits.

Among other things, the AIC will work with relevant agencies to vaccinate home-bound seniors in their own homes.

Its spokesman said: "Most seniors engaged by the Silver Generation Office have generally been receptive towards the vaccination. Those who were less receptive were usually worried about the possibility of side effects."

In recent weeks, however, the resistance has eased, said Lions Befrienders chairman Anthony Tay, in part because of the large number of cases linked to the Bukit Merah View Market and Hawker Centre.

Markets and hawker centres tend to be stomping grounds for seniors. It marked a change from last year when the outbreak was concentrated in dormitories for foreign workers.

Mr Tay said: "Now they feel it has hit close to home and their fear is greater." Besides, as more of their friends remain well after vaccination, they are also more assured and confident of the jab, he said.

Dr Leong Hoe Nam, an infectious diseases specialist from the Rophi Clinic, said that some seniors have not been vaccinated as they are waiting for the Sinovac vaccine, which they feel is safer.

"Sinovac did not publish any reports on adverse effects, so some seniors think it is safer," he said, adding that absence of published data on adverse effects does not mean there are no adverse effects.

Dr Leong said he has had "dozens" of patients from Indonesia who had the Sinovac vaccine and found in subsequent antibody tests that they had little or no immune response to the virus.

A Hong Kong University (HKU) study which tracked the antibody response of 1,000 people who had received either the Pfizer-BioNTech or the Sinovac vaccine also found that people who were vaccinated with the Pfizer-BioNTech vaccine had "substantially higher" levels of antibodies than those who received Sinovac's, Dr Leong said.

Dr Ng Wai Chong, founder of NWC Longevity Practice, a start-up providing aged care consultancy and direct clinical services, urged seniors to be vaccinated, especially since the disease is likely to become endemic.

He said the mRNA vaccines have proven to be safe and effective, with serious adverse reactions being very rare here. The chances of seniors dying from Covid-19 are higher, he noted.

He added: "Even if you don't go out so much, you still have to go out once in a while. And the best protection is still vaccination."