Free H1N1 vaccinations for the general public began in Shijiazhuang, the capital of Hebei province, on Feb 1, the local media reported.

Anyone who lives in Shijiazhuang can obtain a free vaccination from a nearby medical service station, the Shijiazhuang Municipal Disease Control and Prevention Center said.

The fourth shipment of 210,000 doses of H1N1 vaccines arrived in the city, the center said.

More than 4 million people in Hebei have been vaccinated since Oct 28. Most are students, medical staff members and other groups vulnerable to the H1N1 virus, according to the Hebei Provincial Heath Department.

But a comprehensive immune network against H1N1 has not yet taken shape, and there are risks of outbreaks of H1N1 in some areas as the virus continues spreading, said an expert with the department.

People with chronic diseases and others vulnerable to the virus should be inoculated as soon as possible, the expert said.