Everything you need to know about the flu vaccine, including whether it's possible to be infected after getting the shot. Photo / Getty Images
We're officially in flu season.
The season to start getting protected against those nasty winter bugs has commenced and people in at-risk groups are now able to go to their doctor and get the flu shot for free.
For the past few years, New Zealand has had record-breaking, fatal flu seasons. So this year a few changes have been made to the vaccine to try and boost its protection abilities.
News.com.au asked Associate Professor Aeron Hurt from the World Health Organisation's influenza centre what we need to know about the 2018 flu vaccine.
The flu vaccine protects you from four strains of the influenza virus — two type A viruses, called A/H1N1 and A/H3N2 and two type B influenza viruses, called B/Yamagata and B/Victoria.
"These are the groups of viruses that we will see in the coming year," Prof Hurt said.
HOW DO I GET THE VACCINE?
Many workplaces offer a free flu vaccine for employees, but if yours doesn't and you're an otherwise healthy person, talk to your local GP as a charge applies for those who don't qualify, plus the cost of the doctor's consultation fee.
The vaccine is free for some "at-risk" people under the National Immunisation Program.
• Children aged 4 years or under who have been hospitalised for respiratory illness or have a history of significant respiratory illness;
• People under 18 years of age living in the: - Seddon/Ward and rural Eastern Marlborough region (within the Nelson Marlborough - - - District Health Board) - Kaikoura and Hurunui areas (within the Canterbury District Health Board) who have been displaced from their homes in Edgecumbe and the surrounding region
HOW DOES THE VACCINE DIFFER THIS YEAR?
Aside from kids under four being included in the free program, two new "enhanced" vaccines have been created for people over 65 years old, a particularly at-risk group.
"Particularly in the elderly, the influenza vaccine was not as effective as we hoped it would be," Prof Hurt said.
"The real advantage of those two new vaccines for over 65s is they will provide an enhanced immune response and better protection for that group of patients. They are the ones we are most worried about protecting and the ones where the normal vaccines tend not to work quite so well," he said.
CAN THE VACCINE REALLY GIVE YOU THE FLU?
No. It's physically impossible.
"The flu vaccines that are available in New Zealand are inactivated viruses," Prof Hurt said.
"It is impossible for the vaccine to cause an infection because the viruses themselves are dead — they have been killed."
THEN WHY DO SOME PEOPLE GET SICK AFTER HAVING A FLU SHOT?
Getting "sick" or getting a cold is very different to contracting full-blown influenza.
"The time of year when people are getting vaccinated is often at the end of autumn and the start of winter and there are lots of bacteria and illnesses circulating that can cause similar symptoms," Prof Hurt said.
"It's probably one of these other viruses. They might think 'this vaccine has caused me to become ill', but they have been hit by another infection," he said.
"It's also important to note that it can take two weeks to develop immunity after you get the shot. It won't give you immediate protection and it lasts for about six to nine months."
Yes, because even healthy people are being severely affected, even killed by the flu.
"Although the risk is low for otherwise fit and healthy people there is a risk nonetheless.
"More and more what we see is that it is hard to predict who will become severely ill with influenza," Prof Hurt said.
"Of those kids hospitalised last year, about half of them didn't have any underlying illnesses. Fit and healthy people including children can still become severely unwell or be hospitalised."