The complexity of the coronavirus compared with influenza A means those who have recovered from Covid-19 won’t have long-lasting immunity, unlike those infected during the Spanish flu pandemic, a world-leading epidemiologist says.
Infectious disease Professor Sir Roy Anderson says influenza is one third the size of Covid-19, with the coronavirus genome “a much more sophisticated beast”.
The world-leading epidemiologist fears immunity in those who have recovered from a Covid-19 infection will last for an extended period in the way it has been with other viruses.
“With influenza A, if you’ve had one strain you’ve typically got strong immunity to that strain for a very very long time,” he told Breakfast.
He predicted that annual boosters would be a way of life for decades.
“I think the booster doses every year is going to be the way we’re going to go to maintain our immunity to the virus.”
If countries have low vaccination rates, we will continue to see new variants of Covid-19, says Sir Roy.
“The net rate of evolution of any virus is directly proportional to the number of new infections per unit of time.”
With Omicron now in more than 75 countries, he says we have a major global problem.
“The evolution of this virus is going to be continuous, year by year," he said.
“We’re going to get a lot of surprises, there’s going to be new variants coming up all the time.”
Omicron is thought to be more transmissible than Delta, but it remains uncertain how pathogenic, or harmful, the strain is.
“Omicron replicates in the back of the throat and the top of the connection with the throat to the lungs, the bronchial passages,” he said.
“That is the bit of the body where transmission is stimulated, so the greater the viral load in the back of the throat, the more infectious you are to others.”
But he says the replication rate at the bottom of the lungs where the virus causes pathology is lower than Delta, according to preliminary results.
Sir Roy told Breakfast that despite reports that Omicron is highly transmissible but less deadly virus, it is still dangerous and we should not let it spread to create herd immunity.
That argument is flawed, he said.
“Evolution doesn’t take the virus to low pathogenicity necessarily, it takes it to high transmissibility.”
He says the early indications are that Omicron is more transmissible and a little less harmful than Delta but Sir Roy says it is still pathogenic.
Aotearoa recorded its first case of Omicron in Christchurch on Thursday. The case is in a managed isolation facility in Christchurch, with no further cases announced yet.