Watching the doctor inject the Sinovac coronavirus vaccine into his left arm, union leader Tam Kin-chiu said he felt “very happy” on Wednesday.

The light rail driver, who is vice-chairman of the pro-establishment Hong Kong Federation of Railway Trade Unions, said the painless 10-second procedure also gave him a sense of having fulfilled his “social responsibility of getting vaccinated”.

Tam, 55, was one of more than 110,000 people in the city who have been given the mainland-made jab so far.

“I am very happy now as I feel I have stronger protection against Covid-19. I also feel like I’ve fulfilled my social responsibility of getting vaccinated,” he said.

“I don’t feel any pain or discomfort at all, and I hope my participation in the inoculation programme could contribute to the formation of herd immunity.”

Tam was among the 1.3 million people in seven priority groups added to the government’s vaccination drive on Tuesday, taking the total number of residents eligible for the shots to about 3.7 million.

The new sectors were catering, construction, education, tourism, public transport, property management companies and companies running venues heavily affected by social-distancing restrictions, such as gyms and beauty parlours.

Workers in those groups could book slots online to receive either the Sinovac or BioNTech vaccine starting from Tuesday.

The veteran rail driver has been eager to get inoculated ever since late last month when the government said vaccines would be available to certain priority groups.

However, initially officials only included people aged 60 or above, health care workers, public service workers, cross-border transport workers, and residents and staff of care homes. Bus, train, and other public transport workers were not included in the first groups.

“I was very disappointed when I discovered that I was not among the first batch of priority groups,” Tam said. “I really hoped to get the shot as quickly as I could because as a rail driver, I am exposed to a high-risk environment.

“To safeguard the health of myself and other people such as my family and passengers, I hoped to get jabbed quickly.”

When he learned he was eligible, he immediately made a booking for the shot on Tuesday, but government vaccination centres require a company letter proving a person is eligible, so he turned to a private clinic in Tuen Mun which only needed to see his staff identification.

Tam said he did not have any preference about which vaccine to get, and took the Sinovac jab because it was the only one the clinic, which is close to his work, offered.

Tam Kin-chiu shows the spot on his left arm where the needle went in.

Before taking the shot, Tam said the doctor asked him several questions about his health, such as whether he had allergies, chronic conditions, or problems breathing.

“The doctor even asked me if I exercise regularly,” he said. “When he was satisfied that I was fit for taking the jab, he started giving me the shot.

“The jab process was like the blink of an eye and it was done very quickly lasting only 10 seconds. It feels like I didn’t have any dose at all. No pain or irritation.”

After receiving the shot, Tam had to stay for about 30 minutes for observation, and when he told the nurse that he did not feel any discomfort, he was allowed to leave.

Despite growing concerns in the community about possible side effects, especially for those with high blood sugar, high cholesterol, or high blood pressure, Tam said he was not worried about getting the vaccine.

Neither was he put off by the death of three people who had been given the Sinovac shots, believing their deaths were caused by existing chronic illness.

Preliminary findings have shown that two of the fatalities were not directly linked to the vaccine, while government experts were waiting for more reports on the third case.

“I did analyse the data of different types of vaccines,” Tam said. “I believe I am immune to these side effects as I am in good health and I exercise regularly.

About 110,000 people had received the Sinovac vaccine as of Tuesday evening, according to the most recent government data, while more than 3,000 have received the BioNTech vaccine. But take-up rates have dropped over the past few days amid fears over possible side effects.