Influenza vaccines currently used in Hong Kong are safe and effective, and the side effects of flu vaccines are usually mild and transient, the Centre for Health Protection said today.

The centre made the statement in response to media enquiries on the safety of the influenza vaccine.

Centre for Health Protection Controller Dr Edwin Tsui noted the influenza vaccination has been scientifically proven to be one of the most safe and effective ways to prevent seasonal flu and its complications, and can significantly reduce the risk of hospitalisation and death from seasonal influenza, adding that Hong Kong has established a pharmacovigilance system to monitor adverse events following immunisation.

He pointed out that in the past five years, over eight million doses of the influenza vaccine have been administered and there have been no deaths reported after vaccination.

Except those with known contraindications, all people aged six months and above, particularly those who have a higher risk of getting infected with influenza and developing complications, such as the elderly and children, should receive the seasonal flu vaccine every year.

Dr Tsui said: “Severe cases related to seasonal influenza involving adults and cases of severe paediatric influenza-associated complication recorded in the recent flu season were significantly lower than in the influenza season before the COVID-19 pandemic. We believe that this is the result of the general public's willingness to receive the seasonal influenza vaccine.”

Local data showed that the rate of severe influenza complications among children who did not receive the seasonal influenza vaccination of the current season is about four times that of vaccinated children.

Among the elderly, the rate of severe influenza including death among residents of the residential care homes aged 65 years or above who did not receive seasonal flu vaccination of the current season is 2.3 times that of vaccinated residents.

The data highlighted the important protective role of seasonal influenza vaccination against severe infection and death.

Dr Tsui noted that influenza vaccines currently used in Hong Kong, including inactivated influenza vaccine (IIV), recombinant influenza vaccine (RIV) and live-attenuated influenza vaccine (LAIV), are safe and effective.

Traditional IIV has been used for decades. The vaccine has proven to be safe and reliable through repeated testing and quality assessment. The safety of the newer LAIV and RIV is comparable to that of IIV.

He added that the World Health Organization has also indicated that vaccination is the most effective means to prevent serious illness arising from flu.

The side effects of influenza vaccines are usually mild and transient, and the most common include pain and redness at the injection site. Some recipients may experience fever, chills, muscle pain and tiredness. Severe adverse reactions to influenza vaccines are very rare.