SYDNEY — Health authorities in Australia's most populous state have urged people at risk of contracting mpox to get vaccinated amid a spike in cases.

New South Wales (NSW) Health on Thursday reported that there have been 433 confirmed cases of mpox in the state since June 1, the largest outbreak in NSW since its first case of the infectious disease was confirmed in May 2022.

Of those cases, 37 percent were fully inoculated -- having received two doses of a vaccine -- 14 percent had received one dose and 46 percent were not vaccinated.

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"The rapidly rising numbers of mpox cases detected across the state are very concerning, with 26 people requiring hospitalization due to the severity of their symptoms," Kerry Chant, NSW's chief health officer, said in a statement.

"The majority of cases of hospitalization have been among people who are unvaccinated or have received only one dose of vaccine. While cases of mpox are occurring in vaccinated people, the cases tend to be milder and for a shorter period."

She said that no cases of the fast-spreading clade 1b strain of mpox that has been circulating in Central and West Africa have been detected in Australia.

READ MORE: WHO declares mpox global public health emergency

Authorities in Victoria, Australia's second most populous state, in August reported there had been 120 confirmed mpox cases since the start of April. Australia recorded 26 confirmed mpox cases in 2023.