School holidays are coming up which means some of us may be heading on an interstate trip, a European holiday, or a visit to popular destination Bali.

And you may be wondering whether a COVID-19 booster is necessary as an extra layer of defence.

Although it’s not mandatory, experts say travellers should stay up-to-date on COVID-19 boosters given their higher likelihood of exposure to the virus.

Here’s how long it takes for a booster to reach maximum protection and who’s eligible for one.

When should I get my COVID-19 booster before travelling?

Associate professor of public health at the University of Technology Sydney Jane Frawley says you should get a booster two weeks before your holiday.

“Having a booster will drastically reduce the likelihood of getting COVID-19, and if you do get the virus, your symptoms will be mild in most cases.”

Why should you get a booster?

Because travel is a high-risk behaviour.

“For some people, they might not perceive themselves to be at high enough risk to receive a booster,” University of Queensland infectious disease physician Paul Griffin tells the ABC.

“But we do want people to appreciate the risk of travel and the impact of getting sick when you’re trying to enjoy your time elsewhere.”

Dr Frawley says you have to remember travelling often involves crowded environments and poor ventilation — think airports, planes, cruise ships, trains, buses, and hotels.

This is where exposure is at its greatest.

How long does a COVID-19 booster last?

That’s hard to determine.

“It depends on how frequently you’ve been vaccinated, how long ago your last vaccine was, your own immune system, among some other factors,” Dr Griffin says.

“The other thing that affects the performance of the vaccine is when the virus changes — it can be hard to know exactly how long protection lasts.

“But what we do know is that while protection declines over time, that doesn’t mean it disappears to zero quickly.”

This is why the Australian Technical Advisory Group on Immunisation (ATAGI) says most adults (who are not severely immunocompromised) can consider getting a booster every 12 months.

Who is eligible for a COVID-19 booster?

That depends on your age and whether you’re at higher risk of severe COVID-19.

Here are the booster dose recommendations according to the Department of Health:

You can also check your eligibility via the COVID-19 booster tool.

But as always, the best advice is to chat with your GP about your vaccine options.

Which booster should I get? Does it have to be the same as my previous one?

In Australia, we only have one type of vaccine — mRNA — and there are two different manufacturers:

Dr Griffin says those in need of a booster should be getting the monovalent XBB 1.5 vaccine, which uses mRNA.

“Over the course of the pandemic, we’ve had multiple vaccines that targeted different variant/s: the original Wuhan strain, bivalent, and monovalent.

“But right now all we have available since the end of last year is the monovalent XBB 1.5 vaccine which targets a subvariant of Omicron.”

The ATAGI also says XBB.1.5-containing vaccines are preferred over other COVID-19 vaccines.