Table 4.

Quotes from main discussion topics of participant posts (n=434).

Discussion topics and number of posts		Quotation
Vaccination decision (134/434, 30.9%)
	Positive (69/134, 51.5%)	I will take my child for flu vaccination. I also have booked an appointment to take my son for flu vaccination.
	Negative (40/134, 29.9%)	I won’t take my child for flu vaccination because there is still some negative news.
	Being hesitant or seeking opinions for vaccination decision (25/134, 18.7%)	I am considering (whether to take my child for flu vaccination). Then, should I take my child for flu vaccination?
Vaccination clinic and cost (63/434, 14.5%)
	Sharing information (48/63, 76%)	Dr XXX at Kwai Fong, trivalent vaccine is free and quadrivalent vaccine cost HK$60. My child just took the vaccination yesterday, and they still have some available vaccines.
	Seeking information (15/63, 24%)	Which clinics provide free flu vaccination (for children)?
Vaccine safety and side effects (62/434, 14.3%)
	Concerns over vaccine safety and side effects (40/62, 65%)	Is it true that one needs to take influenza vaccination every year once he/she receives the first flu vaccination and that all family members should receive influenza vaccination once one member of the family receives the flu vaccination (otherwise it can be worse)?
	Being mixed or neutral/purely seeking information about vaccine safety and side effects (16/62, 26%)	Different children may have different reactions to the flu vaccination. What can be the side effects of flu vaccination?
	Sharing information for clarifying vaccine safety and side effects (6/62, 10%)	It is misinformation that vaccination can cause autism. This rumor has been dismissed many years before.
Vaccine effectiveness (52/434, 12.0%)
	Concerns over vaccine effectiveness (26/51, 51%)	Now there are too many viruses/bacteria, and they change very quickly. This time, we take the flu vaccination against this virus but later another new virus emerges. How can we ensure that the vaccination is effective? It depends on how accurate their guess on the vaccine strain is every year. If their guess is wrong, the flu shot is a meaningless suffer. If one can still get sick even after taking the vaccination, why should he suffer from an injection?
	Sharing information for clarifying vaccine effectiveness (16/51, 31%)	Although there is mismatch, the vaccine is still effective for preventing influenza H1N1 or influenza B viruses. It (flu vaccination) is an additional protection for our children.
	Being mixed or neutral/purely seeking information about vaccine effectiveness (15/51, 29%)	Is it true that one can still get a cold even after taking the vaccination but can protect against influenza? Can influenza vaccination protect one against serious complications due to influenza?
Medical eligibility for seasonal influenza vaccination (40/434, 9.2%)		I thought to take my daughter for flu vaccination today but she has a running nose and some cough. Is it OK for her to take flu vaccination?
Vaccination experience (33/434, 7.6%)
	Positive (16/33, 49%)	My child has taken the flu vaccination and he still feels very good now.
	Negative (12/33, 36%)	My elder daughter took the flu vaccination once but got more and severe sicknesses that year. Since then, she has never taken flu vaccination...
	Mixed or uncertain (5/33, 15%)	My two sons have taken the flu vaccination. One is 3 years old. He was given injection in the hip and he said no pain. Another is 7 years old. He was given injection in the arm. He said it was very painful and the pain lasted for 2 days.
Doubtful or negative vaccination attitudes (26/434, 6.0%)		Vaccination is to inject germs into the body. Is it necessary to take flu vaccination if my child is always healthy? Too many vaccinations are not good for children.
First-time influenza vaccination (20/434, 4.6%)		I would like to ask: it is my baby’s first flu vaccination. The doctor said he needed two doses of vaccines. Then what’s the maximum time interval between the two vaccinations?