Another school in Guangdong province has been closed after 11 students were infected with H1N1 influenza.
The 11 students in Beijiao Central Primary School in Pengjiang district of Jiangmen city tested positive for the virus on Tuesday.
The school was closed for seven days after a second test confirmed the result on Wednesday.
The school has 1,273 students who study in 24 classes in six grades.
The infected sixth-grade students - eight boys and three girls - are between 12 and 14 years old.
The students are in stable condition and receiving treatment at home, Xie Liangjun, principal of the school, told China Daily Thursday.
"We found lots of students had flu symptoms in the same class when we did our daily morning health check for all students in the school on Monday," Xie said.
About 200 sixth-grade students finished their final tests on Tuesday. Xie said they could miss their graduation ceremony and stay at home until middle school begins in September.
The other students have not yet taken final exams. Xie said the exams would be postponed and held at an appropriate time.
He said the students were busy preparing for exams when they were struck down by the flu and so had not been out much in public.
Another two students at Shipai Township Central Primary School in Dongguan city were confirmed infected with H1N1 on Tuesday.
The school closed for one week on Monday when 30 students there were confirmed infected with H1N1.
Two students at a primary school in Huangpu district, Guangzhou tested positive for H1N1 Thursday.
Twenty-three other students in the school were developing flu symptoms, said Ma Jianfen, an official of Guangzhou health bureau.
The number of cases in Guangdong now stands at 156 after 15 new cases were reported on Wednesday. The province has the highest number of H1N1 patients in the country.
Zeng Guang, a senior epidemiologist at the Chinese Centers for Disease Control and Prevention, said that as China is expecting more such outbreaks at the community level, all parts of the nation are busy implementing specific measures, including administrative and legal ones, to contain further local infections.
Those confirmed or suspected to have the infection who refuse to be examined, quarantined or treated face detention or even imprisonment for up to seven years, according to a notice issued by the Beijing municipal government.