10 open dialogues on flu vaccination

Dr Vivien Chuang, Chief Manager (Infection, Emergency and Contingency)

Beware of flu! To build up defence against influenza, the seasonal influenza vaccination programme for all Hospital Authority (HA) staff and eligible members of the public will start on 10 October and 24 October respectively in public hospitals and general out-patient clinics.

In recent years, more and more colleagues take a flu shot. Last year, the vaccination rate reached 32%. However, some staff are still sceptical about the production, efficacy and side effects of flu vaccine. HASLink has talked to 10 colleagues who share their views about not getting a flu jab. These concerns are responded by Dr Vivien Chuang, Chief Manager (Infection, Emergency and Contingency), with the hope of not only clearing doubts but also making flu vaccination a part of organisation culture.

Get protected, get a jab!

How do I know if the vaccine is genuine or expired?

Seasonal influenza vaccine must be registered in Hong Kong and labelled with a five-digit product registration number (HK-XXXXX).

You can check the packaging information of the vaccine before getting flu jab. The registration record can also be checked on the Government Drugs Office website (www.drugoffice.gov.hk). The shelf life of the vaccine is usually one year and should be stored and transported at two to eight degree Celsius.

Taking flu jab is to inject virus into your body. That is why many people fall sick after vaccination!

The viruses in the inactivated influenza vaccine are dead, which can induce development of antibodies against influenza virus infection in the body. Therefore, flu vaccine does not cause influenza. People will have protection two weeks after receiving flu jab. Some recipients may have mild fever and muscle soreness after injection which are mistakenly considered as influenza infection or falling sick. In fact, these are symptoms of production of antibodies in the immune system.

I am unhealthy and not suitable to take a flu jab.

Except people with known contraindications, such as severe allergic reaction to vaccine component or influenza vaccine, everyone aged six months or above should receive seasonal influenza vaccine for personal protection every year. If you are sick on the day of vaccination, you should reschedule the flu jab appointment until fully recovered.

I am afraid of falling sick after vaccination. It may cause heavy workload to my colleagues.

Influenza vaccine is very safe and usually well tolerated apart from occasional soreness, redness or swelling at the injection site. A small number of recipients may experience fever, muscle pain and feelings of discomfort or weakness that begin 6 to 12 hours after injection. These effects may last up to two days.

If staff get sick from flu, their work will be passed to other colleagues. Moreover, influenza viruses may cause complications or even death in patients who have weak immunity. Healthcare staff getting flu shot can protect themselves and their patients. Supervisors are advised to facilitate frontline colleagues to get vaccinated in turn. Alternatively, colleagues can get vaccinated before holiday or the winter surge.

Scientists ‘gamble’ on the vaccine composition. Why should I do such death-defying act?

World Health Organisation (WHO) runs a series of scientific tests and simulations before selecting influenza virus strains which are likely to be the most prevalent in the upcoming seasonal influenza season. WHO aggregates and analyses the data of local influenza outbreak through a worldwide network of collaborating centres. Meetings take place in February every year to analyse the epidemiology and genetic characteristics of the prevailing influenza viruses, and also of the previous year’s vaccine. They recommend specific vaccine viruses for inclusion in the upcoming vaccines for the Northern hemisphere. After that, manufacturers will produce vaccines. From manufacturing to market supply, it takes about five to six months.

Taking flu jab is not death-defying, but for health protection. When the vaccine strains closely match the circulating influenza viruses, the efficacy of influenza vaccine range from 70% to 90%. Even if there is viral antigenic drift or change, the efficacy rate of flu vaccine can be at least 20%.

I learnt from gossip forum on social media that vaccination can be dangerous to foetus. It is very scary. What if it affects my baby?

Flu shot is safe and suitable for pregnant woman, foetus and breastfeeding mother. The antibodies developed in mother’s body can reduce risk of infection and influenza related complications for the mother and the foetus. A study found that a pregnant woman who gets a flu vaccine is about 51% less likely to experience miscarriage than an unvaccinated pregnant woman. Also, the risk of being hospitalised due to flu of newborns of vaccinated mother is 25% lower for the first six months after birth.

I am a supporting staff and I have no contact with patients. It is unnecessary for me to take a flu jab!

Flu vaccination protects individuals and people around them, most importantly family members. A higher vaccination rate will enhance herd immunity in society. When more people in a community take flu shot, the infection chain of influenza virus can be easily cut off and reduce the spread of the virus.

Why not make flu vaccination mandatory for all healthcare workers if it is so important?

Getting vaccinated is a matter of personal choice. HA encourages colleagues to take flu shot because it is the most effective way to protect themselves and people around them. According to data of the 2017/18 influenza season from Centre for Health Protection, the overall efficacy of flu vaccine for all age groups is 63.4% and 59.3% for influenza type B. The efficacy is considered as medium to high.

I am worried that there is mercury in influenza vaccine! Moreover, taking flu shot every year may develop resistance to targeted therapies against influenza.

The influenza vaccines currently used in Hong Kong is single-dose and do not contain a mercuric compound including the preservative ‘thimerosal’. The protection of vaccine can last for the whole flu season and will not cause any drug resistance. Moreover, as the circulating seasonal influenza strains may change from time to time, the composition of the flu vaccine is updated yearly to enhance protection.

I am very healthy because I exercise every day and have a balanced diet. I do not need a flu shot!

Influenza does not discriminate and can be a threat to anyone no matter you are healthy or not. Even if the flu symptoms are mild, the virus can spread through coughing, sneezing or droplets. In the 2017/18 winter flu season, 74% of the 570 severe adult influenza cases were not flu-vaccinated. So, take care of yourself and the people around you. Get a flu shot as soon as possible!