Beijing, Sep 23 (Xinhua) In their bid to control the fast spreading swine flu epidemic, authorities in China have so far administered H1N1 vaccine shots to more than 39,000 people, an epidemic control expert said Wednesday.

Liang Xiaofeng, director of the immunization centre under the Chinese Centre for Disease Control and Prevention, said as of Tuesday only 14 people developed side effects after taking the vaccine shots.

“We are still investigating the reasons” why there were adverse reactions, Liang said.

He however admitted that there were still doubts about the safety of vaccination for “sensitive groups” such as pregnant and breastfeeding women.

So far, no deaths from H1N1 or swine flu have been reported on the Chinese mainland, but Taiwan has reported 17 deaths of whom two were pregnant women.

On Monday, more than 10,000 students and performers in Beijing who are to take part in the National Day parade Oct 1 received vaccinations, with no adverse reactions, the Beijing Municipal Bureau of Health said Tuesday.

China issued a warrant for mass inoculation with H1N1 flu vaccine Sep 8 after it approved a vaccine produced by domestic pharmaceutical company Sinovac.

There have been more than 13,000 confirmed cases of H1N1 flu reported in China; of them 66.4 percent have recovered already.