The predominant virus strain this winter has caused a particularly aggressive flu season in China. But the outbreak won’t develop into a flu pandemic, as no mutation has been detected in the strains that could affect virus transmission, says an official at National Health and Family Planning Commission.

The high season for the outbreak will continue until the winter school vacation, said Jiao Yahui, deputy head of the commission’s medical administration and management bureau, at a press briefing on Tuesday.

The outbreak is already showing signs of weakening in some parts of the country, Jiao said, attributing the outbreak to multiple reasons, such as temperature changes and the dominance of the B/Yamagata strain, which had not been prevalent for many years.

Experts recommend vulnerable people get flu shots as an important way to prevent the H1N1, H3N2, and B/Victoria strains, the three dominant strains last year.

However, these vaccines have limited effect against B/Yamagata, said Li Zhongjie, who is with the Chinese Center for Disease Control and Prevention (China CDC).

China CDC is encouraging the development of vaccines that can prevent all four strains, and at least one mainland company might be able to produce such a vaccine this year, said Feng Zijian, a deputy head of China CDC.

The country has 557 monitoring sites and more than 400 online labs to detect, report, and identify the flu virus, said Liang Xiaofeng, another deputy head of China CDC.

Jiao said domestically produced medications are effective to cure the flu, adding that the commission has asked local medical institutions and health and family planning departments to open up temporary channels for local medical institutions to procure drugs in order to ensure adequate supply of the medicine.