HANGZHOU - China's Zhejiang Province ordered an immediate freeze of 2,880 doses of a US-made children's vaccine for fear of contamination on Monday.

Zhejiang Provincial Disease Control and Prevention Center officials said none of the purchased doses in the batch made by drug company Merck had been used and all were frozen in the eastern coastal province.

The New Jersey-based company announced last week that it had initiated a voluntary recall of 11 lots of its Haemophilus influenza type B vaccine, PEDVAXHIB, and two lots of its combination Haemophilus influenza type B/ hepatitis B vaccine, COMVAX.

"Merck is conducting this recall because it can not assure sterility of these specific vaccine lots," the company said in a statement on its website. "The potential contamination of these specific lots was identified as part of the company's standard evaluation of its manufacturing processes. Sterility tests of the vaccine lots that are the subject of this recall have not found any contamination in the vaccine."

The affected doses were distributed from April, it said.

China imported 104,930 questionable PEDVAXHIB doses with the batch number J2438, according to a Beijing Morning Post report on Monday.

The State Food and Drug Administration issued an urgent notice on Sunday ordering a stop to the use of doses that were sold to Beijing, Tianjin, Shandong, Zhejiang, Fujian, Guangdong, Hainan and Sichuan.

Health authorities in south China's Guangdong Province have frozen nearly 19,220 doses, while 7,120 others were sold earlier. No cases of adverse reactions to the vaccines have been reported.

In Beijing, 2,580 of the 2,640 doses purchased were frozen.

PEDVAXHIB was indicated for routine vaccination against an invasive disease caused by Haemophilus influenza type B in infants and children two to 71 months of age.

The most frequently reported adverse reactions were fever, irritability, sleepiness and soreness, redness or inflammation, swelling or hardening of the skin around the injection site.

Children could also emit an unusual high-pitched or prolonged crying and suffer diarrhea, vomiting, infection or inflammation of the ears, rash and upper respiratory infection, it said.