File photo. Photo: 123rf
An immunologist says the risk of being reinfected with Covid-19 is on the rise because immunity is beginning to wane as time drags on since people's last infections and boosters.
More than 20,000 cases of the virus were reported this week, and around 10 percent of those were reinfections.
Cellular immunologist Dr Anna Brooks told First Up, Aotearoa now had a "variant soup" which increased the chance of people becoming reinfected.
Countries which were tracking reinfections more closely that New Zealand was had seen evidence the new variants were driving those reinfections, she said.
"When you've got various variants circulating, you're going to have more chance of getting a variant that evades the immune system."
Those who had managed to avoid being infected with Covid-19 so far were also at risk, Brooks said.
"There are many people who have evaded getting infected and that choice, if you like, of remaining uninfected in a society that has so-called 'moved on' is going to become difficult."
She said it was a concern some people had to be over the age of 50 to receive a second booster, because the immunity of those who were boosted some time ago would be waning.
"That can be frustrating for the diligent evaders of getting infected."
People should ensure they were up-to-date with any booster shots they were eligible for, she said, and masking also remained "critical".
"There's this complacency that just because we're in summer and we're less likely to be congregating indoors ... that we're less likely to get infected...
"We saw all through the summers around the world - it did not stop Covid waves, and it's not going to stop Covid waves here."
Brooks said she would have liked to see more surveillance of the new subvariants turning up in New Zealand.
"Essentially, every time a variant or subvariant emerges, it's because it's gained mutations to escape the immune system," she said.
"Each demographic's going to have different susceptibilities depending what variants are within your community and whether you have any immunity to it."
It was "a bit hard" hearing the concept that hybrid immunity protected people, Brooks added.
"Hybrid immunity's an outcome and should never be an aim...
"There are plenty of vulnerable people ... a large percent of society who still want to avoid getting infected, because infections are never a goal."
