Pfizer Inc is ceasing its commercial vaccine operations in China after the government failed to renew its license for a key shot for children, the latest sign of the uncertainties facing international drugmakers in the nation.

The Chinese import license for the Prevenar-brand vaccine expired last year, the US pharmaceutical company said in a statement on Thursday. It expects a shortage of the product in China before the launch of a newer version, called Prevenar 13, that it already sells in other parts of the world.

Drugmakers in China have faced delays in approvals in recent years because of changing rules. At least thirty-four applications from foreign multinationals have been or are set to be delayed after Chinese regulators began requiring an added procedure, according to R&D-Based Pharmaceutical Association Committee.

"This won't have too big an effect on the children's immunization process" as the drug is not included in China's vaccination program, said Shi Lichen, a manager at Beijing Dingchen Medical Consultancy, a privately run company that gives advice on the industry.

While Prevenar is the only vaccine for pneumococcal disease approved in China for children under two, no data proves infants have a high infection rate, Shi said. China has a much cheaper vaccine available for older children, he said. The US Centers for Disease Control and Prevention recommends the vaccination for youngsters under 5 years old. Pneumococcal infection can lead to potentially fatal sicknesses such as pneumonia, blood infections and meningitis.

An official at the China Food and Drug Administration's media office said it could not immediately comment.

The effect of the lost license on Pfizer might be more pronounced as Prevenar is the only vaccine the company sells in China. Most of the 200 employees at its China vaccine business will be "affected" and it will work to help those affected to find new roles at its other business units, the statement said.