Two new cases of community transmission were diagnosed in Queensland overnight, including a nurse who had been vaccinated against COVID-19.

Annastacia Palaszczuk said both are linked to known cases and that the nurse who works at the Princess Alexandra Hospital had received the vaccine.

Genomic sequencing revealed she has the same strain as another PA Hospital nurse who tested positive earlier in the week.

It’s unclear whether the second nurse had received both doses of the COVID vaccine. The first nurse had only received her initial dose.

Chief health officer Jeanette Young said health authorities are now trying to determine whether the nurse caught it in the same ward.

“She was tested as part of the asymptomatic screening testing process for that ward and was found to be positive,” she said.

“She has since developed some symptoms, but she was part of that testing.

“So we just need to work out how she got it … she had been vaccinated prior to working that shift.”

Ms Palaszczuk and the state’s health authorities are due to decide on a possible extension of the lockdown on Wednesday evening but previously warned a further escalation of cases could see this strict directive pushed back.

She said she would address Queenslanders on Thursday morning and hoped things could return to normal for the holiday break.

In Wednesday’s media address she said minimal transmission was “encouraging news”.

“The fact we do not have any unlinked community transmission in the southeast or in our state is absolutely encouraging news,” Ms Palaszczuk told reporters.

“We are doing a great job and together we will get through this.”

Vaccines against COVID-19 are about 90 percent effective at blocking coronavirus infections.