Shanghai has entered the annual influenza season, but the situation is "stable and under control," according to the Shanghai Center for Disease Control and Prevention.
The H3N2 flu virus has become the predominant influenza strain in the city during the summer flu season, which is expected to end next month, said Pan Hao, director of the SCDC's communicable disease control and prevention institute.
The proportion of flu infection rose sharply in July compared with June, according to the SCDC. That increase was higher than seen in 2016 but lower than 2015 and 2014, the center announced yesterday.
"The flu spread in the city is stable and controllable," Pan said. The H3N2 virus, which led to seasonal flu, has become the most prevalent strain in the city since July and should enter a downturn next month, he added.
Concern has risen over the outbreak of seasonal influenza after Hong Kong reported more than 300 summer flu-related deaths from May 5 to August 6. Some 450 series flu infections have been recorded in Hong Kong during the period, according to the Center for Health Protection under the special administrative region's Department of Health.
Some news reports claimed that the summer flu in Hong Kong had killed more people than the SARS epidemic did in 2003. Pan said this year's situation was totally "incomparable" to the outbreak of severe acute respiratory syndrome in 2003, and the reported number of cases in Hong Kong this summer wasn't abnormal compared with previous years.
The number of deaths during the winter flu season reached 442 in 2015 and 171 in 2016, according to Hong Kong CHP records.
Pan added that the situations are different in Hong Kong and Shanghai, though the dominating flu strain is the same. The Hong Kong authority has confirmed the H3N2 virus hasn't mutated.
"Our latest surveillance data show that, after its peak in mid-July, the influenza activity has been on the decline as most parameters including laboratory surveillance, influenza-associated hospital admissions and institutional outbreaks have been decreasing in the past two to three weeks," said a CHP spokesman in Hong Kong.
Shanghai usually has two flu seasons — in summer and winter, while Hong Kong usually has one peak period in summer, Pan said. The northern Chinese regions usually experience the flu outbreak in winter since people are likely to stay indoors which encourages the circulation of the virus.
In southern regions, however, influenza often becomes rampant in summer because air-conditioning lowers the body's immunity.
Shanghai sits in the middle of the nation's north and south, so suffers two flu seasons every year, Pan said.
The next winter flu season is expected to hit the city from November to February, he added.
To prevent the infection, children and seniors over 60 years old are advised to avoid crowded public areas during the flu seasons.
People should wear masks, especially in the flu epidemic regions like Hong Kong, and constantly wash their hands.
Children, seniors and those who are in contact with flu patients such as doctors and taxi drivers should have flu vaccines, which can resist the virus for about eight months.
Local residents are advised to take the shot around October, according to the SCDC.