MELBOURNE: When most of us get the flu, we spend three or four days on the couch feeling miserable, then we bounce back pretty quickly.
But others have more severe symptoms and need to be hospitalised because they’re at risk of life-threatening complications. Some people even die from the flu.
The size and impact of influenza seasons varies from year to year. In 2017, Australia had its worst flu season for 20 years, with at least 1,255 lives lost. The 2018 season was relatively mild, but it doesn’t seem to have ever ended.
The best way to protect against influenza is to get a flu vaccine each year. It’s not as effective as some other vaccines, but it reduces your risk of getting the flu by around 60 per cent.
Protection often will have begun to wane four or five months later, so getting vaccinated early, will give you better protection at the height of the flu season. But there are number of factors to consider before deciding when to get your flu shot.
WHY GET A FLU SHOT EACH YEAR?
Influenza viruses change each year and the vaccine is updated to keep up with these changes. This year, for example, the vaccine protects against two different strains than the 2018 vaccine.
Our body’s immune response to the vaccine also wanes over time. So even if you were vaccinated, you may no longer be fully protected 18 months later, depending on your age and your response to the last vaccination.
In many countries, influenza vaccines are usually available in early April, or even in March.
In mid-April, stock typically starts arriving at GP clinics and polyclinics. Many countries also offer free vaccination to some people, including children, the elderly and those at risk of complications.
GET VACCINATED EARLY
Getting a vaccine immediately after it becomes available will ensure you don’t miss out if there’s a vaccine shortage.
But there is a potential downside. Protection against influenza peaks one to two months after you have your vaccine, and then declines. This rate of decline varies from person to person, by age, and by influenza strain.
There are few good quality studies across all ages to measure this rate of decline accurately, although a study from 2015 showed that the measurable antibody responses to the influenza vaccine components reduced slowly.
Another study from 2014 showed the vaccine was less effective in people vaccinated three or more months earlier, adding to the evidence that protection wanes over time.
If you delay your decision to be vaccinated, however, chances of becoming infected will significantly increase.
Don't forget, it takes seven to 10 days from the time of your flu shot for the vaccine to begin to be fully effective.
VACCINATE KIDS A MONTH EARLIER
Vaccination timing is a little different for children. Those aged six months to nine years who haven’t been vaccinated against influenza before need two doses of vaccine, four weeks apart. So they will need to start their vaccination programme a month earlier than adults and the elderly.
If you want to get vaccinated in 2019, there’s no need to rush, but it’s better to be vaccinated early than not at all.
Your GP or pharmacist will advise you on the most appropriate vaccine and the best timing for you.
Dr Ian Barr is the Deputy Director of the WHO Collaborating Centre for Reference and Research on Influenza located in Melbourne, Australia. A version of this commentary first appeared on The Conversation. Read it here.