With Australia on track for a killer flu season, families, schools and workplaces are heeding the advice of experts and organising their flu shots early.

That might raise a few questions, such as:

Where is the best place to get a flu shot?

Where is the best place to get a flu shot? What if I'm sick on the day of my appointment?

What if I'm sick on the day of my appointment? Why do they ask if I have an egg allergy?

Why do they ask if I have an egg allergy? Why do I feel sick for days after?

Here are some answers.

Can I still get a flu shot if I'm sick?

Once you have booked your appointment, you are required to fill out a screening questionnaire, a standard list of questions recommended by the Australian Immunisation Handbook.

The questionnaire is mandatory because a needle cannot be administered without your express consent. As part of it, an administrator will generally ask how you are feeling.

A few sniffles should not prevent getting a flu vaccine. ( ABC News: Kym Agius )

But it can be hard to know whether it is worth mentioning your runny nose (especially if you don't have time to reschedule the appointment).

It all depends on how sick you are: a runny nose, cough, and aches and pains will not prevent you from receiving the vaccine, but having a high fever will.

"If you are 'systemically unwell' or have a fever of above 38.5C, it's medically recommended that we hold off," Dr Clements said.

However, an administrator can choose not to give you the vaccine if they suspect you are ill, even if you say you are fine.

Some vaccines are better suited than others

Michael Clements, a GP and spokesperson for the Australia Medical Association Queensland, said there is a difference between the flu vaccines you pay for, and those that are free.

Dr Clements said the best vaccine is the free one offered by the Government to those who are eligible — that is, people aged over 65, under the age of five, and those with chronic illnesses.

These vaccines are considered superior by doctors because they are specially purchased by the Government to meet the specific needs of those groups.

For example, those aged over 65 need a stronger vaccine compared to the rest of the population.

The vaccine for the rest of the population — available from a GP, pharmacy, or offered by an employer — can be provided by different brands through private contracts.

Dr Clements said, vaccines are considered inferior for over-65s, children and the chronically ill, they are completely fine for the fit and healthy population.

It's important to note that all influenza vaccines administered in Australia are approved by the Therapeutical Goods Administration.

What do eggs have to do with it?

The questionnaire will also ask if you are allergic to eggs, among other things. That is because the flu vaccine may contain residual egg protein because it is grown in eggs.

In fact, all influenza vaccines available in Australia are prepared from purified inactivated influenza virus that has been cultivated in embryonated hens' eggs.

If you are allergic to eggs, it may affect how you get your flu vaccine. ( Supplied: Australian Eggs )

The vaccine is grown in eggs because a virus cannot reproduce on its own, it has to infect a cell and take over that cell, and tell the generic material in that cell to make new viruses.

Emeritus Professor and Burnet Institute Visiting Fellow Greg Tannock, who sits on the Australian Influenza Vaccine Committee (AIVC), said "about 90 per cent of influenza vaccines use, as starting materials, influenza viruses grown in the allantoic sac of 10 to 11-day-old fertile eggs."

Other vaccines grown in eggs are:

Pandemic inactivated influenza vaccine (H1N1, bird or swine flu vaccines)

Pandemic inactivated influenza vaccine (H1N1, bird or swine flu vaccines) Yellow Fever vaccine

Yellow Fever vaccine Q fever vaccine

Luckily not many people are allergic to eggs.

While it is relatively common in infants — 8.9 per cent having a proven allergy to raw egg — most kids outgrow it by the time they reach primary school, although it can sometimes persist into adult life.

Over the past few decades, the amount of egg protein used in the vaccine has been greatly reduced to less than just 1 microgram (one-millionth of a gram) per dose.

Severe allergic responses are also very rare.

According to ASCIA, there might be some mild and occasional side-effects such as local itching, mild hives, throat irritation, wheezing or abdominal pain — but the risk of anaphylaxis is very low, estimated at 1.35 per million doses.

"They certainly do not constitute a reason for abandoning vaccination, because of the major public health consequences of influenza epidemics.

Dr Clements said there are relatively few allergies that would prevent an influenza vaccine.

If you have an anaphylactic reaction to eggs, you must get your vaccine in a medical facility where they can monitor you afterwards and, on the off chance it is needed, have access to resuscitation medication.

Feeling sick the day after a vaccine? Good

Dr Clements said this is a sign the immunisation is working.

"We know that around 10 per cent of people who have the vaccine will feel a bit off for a couple of days, and they may feel a fever and aches and pains, and may feel a bit worse for it — but what they're actually feeling is their body's immune system working — and that's a good sign," he said.

"The feeling normally only lasts for a couple of days and it's the body's sign it's fighting the virus."

Dr Clements said it was important to remember the influenza vaccine can be up to only 60 per cent effective, and even then it wears off in just four to six months.

But he said it is still important as many people as possible get vaccinated because that percentage is still worthwhile.

"Every day now I'm diagnosing people with influenza, and for most people it's a nuisance but for some its a terminal diagnosis," he said.

"So I tell my patients; even if you're not getting the needle for you, get it for your grandma or niece or nephew."

What's the go with lollipops?

Do lollipops provide a kind of placebo effect after a vaccination? ( Supplied: Unsplash )

The little treat you leave with after a jab provides no physical or psychological benefit. So where does this come from?

"It's a mix of tradition, bribery and fun," Dr Clements said.

"There is a little bit of evidence for sugar as pain relief for children, and that's probably where the tradition started … but it's mostly bribery.

"Children three and above normally respond well to bribery … and most of us don't tend to grow up."