BEIJING, March 12 (Bernama) -- People with chronic diseases, the obese, and pregnant women face a renewed threat of contracting deadly infection of A/H1N1 influenza as spring draws near, reports Xinhua news agency on Friday.

Severe and fatal cases peaked in early and mid December last year, and have been dropping gradually since, but the disease threatened a resurgence as the weather warmed up, senior epidemilogists have warned.

"A new outbreak of A/H1N1 influenza is possible during this winter-spring season, and especially in the southern areas during summer," said Shu Yuelong, director of the Chinese National Influenza Center, which is affiliated with the Ministry of Health, at a meeting.

Cases of patients with chronic diseases, pregnant women and obese people were much more likely to become severe or even fatal.

Pathogenic studies showed a very small chance of the A/H1N1 virus mutating during this winter and spring, so vaccination was still essential to prevent potential outbreaks.

Analyses of past flu outbreaks showed a pandemic usually lasted more than two years before turning into seasonal flu, said Shu.

"So the A/H1N1 influenza might be prevalent in the world for a considerably long time."

Experts said the government should promote vaccinations for high-risk groups, people in rural areas and migrant workers in urban areas.

According to the Chinese Center for Disease Control and Prevention, about 35,000 pregnant women and 37,000 children aged six months to three years had been inoculated with the A/H1N1 flu vaccine and no severe adverse reactions had been reported.

As of March 7, the Chinese mainland had reported a total of 127,427 cases of A/H1N1 flu, of which 8,320 were severe and 796 people had died.