China's drug watchdog said Tuesday that revaccination was underway after 210,000 rabies vaccines were found with lower potency.

China's State Food and Drug Administration (SFDA) Spokeswoman Yan Jiangying told a press conference that seven batches of rabies vaccines, manufactured by two biopharmaceutical companies in northern Hebei and eastern Jiangsu provinces respectively between July and October last year, contained lower amount of medication.

"After inoculated, the level of immune antibody is lower than the standard so the vaccine cannot have the same efficacy of rabies prevention," Yan said.

She said the Ministry of Health and the SFDA had already distributed 210,000 new vaccines nationwide to revaccinate people.

Yan said those who had been inoculated with the substandard vaccines should consult doctors, who would decide whether a revaccination was necessary due to individual differences.

She also reassured the public that prompt revaccination could take effect in theories as these substandard vaccines could still produce some antibody though they were lower than the standard amount.

People bitten by cats or dogs should be immediately vaccinated to prevent the infectious disease.

Yan did not mention the investigation result over the substandard vaccines. The SFDA said last week that it would seriously deal with the case and the police would start investigation if any crimes involved.

No adverse reaction has been found so far, according to local drug regulators.