Covid 19 Australia: New Covid strain confirmed in NSW prompts concern over reinfection rates

A new coronavirus subvariant of the Omicron strain has arrived in NSW leading health experts to issue a warning about the increased risk of reinfection in the community.

A traveller returning from South Africa in the last week of March tested positive for the BA.4 subvariant which has been flagged by the World Health Organisation.

NSW Health took three weeks to confirm the case as the first recorded instance of the new variant.

The WHO has warned that the new strain may contain mutations that may be better at evading the immune system in those that are already vaccinated.

Former WHO epidemiologist, Professor Adrian Esterman said the new subvariant is rapidly overtaking the BA.2 variant in Africa and South Africa.

"It appears to have same intrinsic transmissibility as BA.2, but can more easily evade immunity – that is, it can more easily reinfect people, or infect those who are vaccinated," he told NCA NewsWire.

NSW Health does not make public the number of people who have been reinfected.

However, Victoria has reported almost 10,000 Covid-19 reinfections in the three months to March 2022.

Esterman compared the reproduction rate of the subvariant to measles, widely recognised as the most contagious viral disease.

He said the severity of disease experienced by those infected with the new subvariant is reportedly the same as that experienced by those infected with the BA.2 variant.

However, there is anecdotal evidence of more children being hospitalised with this variant.

NSW Health reported 13,771 new Covid-19 cases and a further 19 deaths on Thursday.

Victorian health authorities confirmed the detection of the new Omicron subvariant at the Tullamarine wastewater catchment.