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COVID-19 reinfection, the 4th vaccine dose, and antiviral medications—what you need to know

A graphic showing a hierarchy or tree of how disease spreads from one person to others

Even if you've had COVID-19, you can get it again.

Will you have natural immunity? How much will your natural immunity protect you, and for how long? Will you have milder or more severe disease? Does the vaccine boost your natural immunity? Do you need antiviral medication?


Surveillance data has confirmed COVID-19 reinfection is occurring, particularly with the emergence of new strains that can evade immunity from previous infections.

Reinfection means you were infected with the virus that causes COVID-19, recovered, and then became infected again at a later date.

After you recover from COVID-19, you do have some natural immunity to protect against repeat infection. A recent study suggests a lower risk of reinfection and hospitalisation for up to 20 months after COVID-19 infection. Natural immunity wanes over time and wanes more quickly in elderly people and in people with diseases affecting the health of their immune system. Because COVID-19 is a relatively new disease, not enough time has passed to fully research the natural immunity following infection, how strong it is, and how long it lasts.

There is some evidence that the period of time you may be protected against reinfection following a COVID-19 infection is shorter with new variants of the virus, particularly the Omicron BA.4 and BA.5 subvariants.

A statement by the Australian Health Protection Principal Committee (AHPPC) on 8 July 2022 said: ‘Omicron BA.4 and BA.5 are associated with increased immune escape and we are likely to see rates of reinfection rise among those who have previously been infected with an earlier COVID-19 variant and those who are up to date with their vaccinations.’

Most jurisdictions in Australia, including Queensland, have now reduced the reinfection period from 12 weeks to 28 days (4 weeks) in line with the AHPPC’s advice. If you’ve recovered from COVID-19 and get symptoms again, you should stay at home and get tested for COVID-19.

Symptoms and disease with reinfections may be less severe. But this is not always the case—you may become severely ill with a reinfection, which is likely to be a different strain.

Reinfected people may still put themselves and others at risk when they have mild symptoms if they do not test for COVID-19 and follow the health advice. It’s important to remember that it’s not just your health you are protecting, it’s also the people around you, particularly the vulnerable, as well as essential workers such as hospital staff.

Research indicates that the risks of reinfection and hospitalisation are lower if a person who has had COVID-19 has also been vaccinated. The risk is further reduced with each additional dose of vaccine, including boosters.

Recovered from COVID-19 and have symptoms again?

  • If you get symptoms again after you've recovered from COVID-19, stay home. If you have recovered from COVID-19 more than 28 days ago, or you are advised to do so by your healthcare provider, then you should get tested.
  • If you get a positive result, complete 7 days of isolation. If you have a negative result, stay home until you no longer have symptoms.
  • If you have been told you are a close contact of someone who has COVID-19, follow the guidelines for close contacts.

Fourth vaccine dose

It’s important to keep your COVID-19 vaccinations up to date, which means having all boosters you are eligible for. Getting boosters will provide an extra layer of protection against COVID-19.

  • All Queenslanders aged 16 and over who have had 2 COVID-19 vaccine doses more than 3 months ago should get a third COVID-19 vaccine dose (first booster).
  • People aged 50 and over, and those at greater risk of severe illness, are recommended to have a fourth dose (a second booster, also called a winter dose).
  • People aged 30 to 49 can also get a fourth dose (second booster) if they choose.
  • Even if you’ve had COVID-19, you should still get your boosters after an interval of 3 months.
  • Children aged 5 to 15 should get two COVID-19 vaccine doses. Boosters are not currently recommended for this age group unless they are immunocompromised, have a disability with significant or complex health needs, or have severe, complex or multiple health conditions that increase the risk of severe COVID-19. Discuss boosters for children with your doctor.

Antiviral medication

Oral antiviral medicines for COVID-19 are now available for people at higher risk of developing severe illness. These medicines can reduce the need for you to go to hospital, and if given on time can prevent severe illness.

These medicines are recommended if you have COVID-19 and are:

  • 70 years of age or older
  • 50 years of age or older, with two other risk factors for severe disease
  • you identify as a person of Aboriginal or Torres Strait Islander origin, are 30 years of age or older with two other risk factors for severe disease
  • 18 years or older and immunocompromised.

Risk factors for severe disease include:

  • diabetes
  • being significantly overweight
  • serious heart disease
  • chronic respiratory disease
  • chronic kidney disease
  • living with disability with multiple conditions
  • other serious health problems

Get ready now

Treatment needs to start within five days of developing symptoms or testing positive to COVID-19. Plan ahead and talk with your medical team now about what to do if you catch COVID-19. This can be your:

  • general practitioner (GP)
  • nurse practitioner
  • treating specialist

These treatments are not a substitute for vaccination. We know that vaccination, and especially getting boosted, is still your best protection against severe COVID-19.

After testing positive to COVID-19

If you believe you are eligible for antiviral medicines, don’t delay. Learn about the important steps to protect yourself and others.

More information

Last updated: 22 July 2022