Eight new human H7N9 cases were reported on Tuesday in three provinces in China.

The eastern province of Zhejiang reported 4 new cases, including a 43-year-old woman in Hangzhou City, an 81-year-old man and a 63-year-old woman in Huzhou City, and a 57-year-old man in Ningbo City, according to the provincial health and family planning commission.

The new cases brought the number of infections in the province this year to 53, according to the commission.

Three more new cases were reported in Shenzhen City, Guangdong Province, according to the provincial health and family planning commission. They include three women aged 43, 41 and 31.

Another case, a 53-year-old man, was reported in Huai'an City, Jiangsu Province.

H7N9 bird flu has already killed 19 in China this year, and the total number of human infections had reached 96 as of Monday, according to the Chinese Center for Disease Control and Prevention.

Shu Yuelong, director of the Chinese National Influenza Center, said on Monday that a large-scale H7N9 epidemic is unlikely during the Spring Festival holiday, as no H7N9 virus mutation that could affect public health has been identified so far.

With bird flu cases increasing on a daily basis, China has stepped up its vaccine research for H7N9.

Hualan Biological Engineering Inc. said in early January that the H7N9 vaccine developed by its subsidiary, Hualan Biological Bacterin Co., Ltd., had passed an initial examination by the food and drug watchdog in central China's Henan Province.

The vaccine is currently being handled by the China Food and Drug Administration, but it is still hard to say when the vaccine will be approved for production, according to the Henan Provincial Food and Drug Administration.

Chicken has been a requisite dish on Chinese dining tables for centuries during Spring Festival, which begins this Friday.

Chinese farmers have traditionally raised chickens using free range methods, especially in the countryside, which has been deemed by experts as a potential risk for spreading bird flu.