In South Korea, a number of people presented serious reactions after receiving influenza vaccination, while dozens of them died. The jabs linked to some of the fatalities were produced by renowned pharmaceutical firms. This has created much concern for many of the Hongkongers who plan to get a shot as we brace ourselves for the winter flu surge: is the vaccination risks acceptable?

There is no doubt that influenza vaccination carries risks. But before deciding whether taking the vaccine or not, we should understand what exactly these risks are.

Risk 1: Quality of vaccine

Vaccines can be contaminated during manufacturing, transport or storage. The desirable temperature for vaccine storage is 2 to 8⁰C. If vaccine is left outside this range for too long, their potency may be lost or even cause harm if injected.

In Hong Kong, the Department of Health executes strict regulations and monitoring for imported vaccines, and pharmaceutical companies also take great care in maintaining the “cold chain”. This risk is therefore largely controllable, and we do not need to worry too much about it.

Risk 2: Different Individual reaction towards vaccination

This varies from mild symptoms of rash and fever to drug reaction, and in a handful of people, they may even become paralyzed with a condition known as Guillain-Barré syndrome.

To minimise this risk, people are usually screened for protein allergy before they receive flu jab, but even so, it is largely unpredictable. That said, does it mean we should avoid vaccination?

Risk 3: Risk of being unvaccinated

One thing we must understand, just as there are risks associated with receiving vaccines, so are there  risks of not receiving them. We must compare both in order to make a reasonable decision.

The chance of having sustained severe reactions after flu jab is 1 in 100,000 to 1,000,000, while deadly cases are even more rare [1]. On the other hand, according to the 2018/19 data of the United States Center of Disease Control[2], influenza can cause, depending on age, 0,4 to 48.7 death per around 100,000 infections; the rate of hospitalisation is even higher, at around 39.2 to 533 cases per 100,000 infections. Understandably, the risks for subgroups such as children, elderly and those with chronic illnesses will be higher. All in all, based on existing evidence, medical experts around the world do believe the benefit of receiving influenza vaccination exceed its risks by far.

Finally, we must recognise the protection of flu jab is not 100%. That is why we should remain vigilant and always observe universal masking, hand hygiene and social distancing to ensure maximum protection, even during the time of COVID-19 pandemic. 

Remarks:

[1] https://immunizebc.ca/side-effects

[2] https://www.cdc.gov/flu/about/burden/2018-2019.html