Home Immunity Waning Covid-19 immunity, new variants mean ‘tough race’ ahead – immunologist

Waning Covid-19 immunity, new variants mean ‘tough race’ ahead – immunologist


An immunologist warns that ‘we are going to take a beating’ as new variants of Covid-19 and declining immunity make it more likely that people will be infected or re-infected with the virus.

Immunologist and director of the Malaghan Institute, Professor Graham le Gros.
Photo: Provided

The Department of Health said the highly transmissible BA.5 subvariant of Omicron would become the dominant strain of the virus in New Zealand within weeks.

Yesterday the Department of Health reported 6,223 new Covid cases, 254 of which were reinfections of people who had the virus before.

Immunologist and director of the Malaghan Institute, Professor Graham le Gros, said the virus had evolved and people had been infected with previous versions of Covid-19.

“The one that’s circulating now has changed so much that that immunity doesn’t work as well and when you add the factor that the immunity that was generated either by the previous virus infection or by the vaccine, it wears off over a period of six months – it seems to be a very short-lived immunity.”

This meant people were susceptible to infection with new variants, Le Gros said. The first standing.

Health advice now suggests that reinfection can now occur within 29 days of recovering from Covid-19.

People were in a better position than when the virus emerged two years ago, Le Gros said, but immune systems were catching up trying to cope with the new variants.

“With the new variants, you’re just trying to move forward and that’s the nature of the immune system’s evolutionary race against the virus.”

It was a difficult time with the flu virus circulating in the community as well, Le Gros said.

But people had to do what they could to avoid getting viruses and the most important thing to avoid Covid-19 was getting a booster shot, he said.

“The other is to avoid places where a lot of people are talking very enthusiastically and without a mask.”

People with weakened immune systems should be especially careful not to become infected with Covid-19 because it can take much longer than usual to clear the virus, Le Gros said.

Everyone should be aware of that, though, and that’s why mask-wearing was so important, he said.

A growing number of older people were now catching Covid-19 as the country was no longer on lockdown, Le Gros said.

“But I think we have to work with this cause we can’t stay locked up forever.”

Le Gros’ advice for avoiding the virus was to make sure a person had both boosters if they qualified, to make sure they slept and ate well, didn’t drink too much, wore a mask and stayed away from large unmasked crowds.

New Zealand’s per capita Covid-19 death rate is higher than Victoria’s

Australian epidemiologist Tony Blakely said New Zealand had a higher Covid-19 death rate per capita than Victoria – and it was not obvious why.

Blakely co-wrote a paper with New Zealand epidemiologist Professor Michael Baker, saying there is a real risk that current settings will not be enough to prevent health services in both countries from being overwhelmed.

The per capita hospitalization rate for people with Covid-19 in New Zealand and Victoria state was currently about the same, Blakely said. morning report.

But he said that per 100,000, New Zealand’s death rate was 20% higher than Victoria’s.

The reason for this was unclear, although it could be due to a number of factors, he said.

Assigning a cause of death was surprisingly difficult and it could usually take up to a year for authorities to do so, but it had been accelerated due to the pandemic, he said.

Unlike New Zealand, Victoria attempted to split deaths into people who died with Covid-19 and people who died from Covid-19, Blakely said.

“New Zealand may have slightly higher rates due to a larger proportion of the Maori and Pasifika population and also lower socio-economic status, which increases your death rates, people with comorbidities, with high obesity rates, it could be things like that too.”

Another reason could be that Covid-19 infections rose in Australia earlier than in New Zealand, which has been Covid-19-free longer, he said.

This meant that New Zealanders could have less overall immunity to the virus because “if you were naturally infected and vaccinated, you have a bit better immunity than if you were ‘just vaccinated'”.

However, compared to other countries, New Zealand and Australia were doing well and had a low cumulative death rate due to their earlier zero Covid strategies, Blakely said.

“We are now learning to live with the virus which is by definition messy.”

Both Tasman sides were doing well in rolling out vaccinations and rules for the third and fourth boosters and in rolling out antiviral drugs, Blakely said.

“Where there is controversy and debate is over whether masks should be mandatory or encouraged.”

Blakely said a game-changer would be vaccines that prevent people from getting infected, rather than just preventing them from getting seriously ill.

“What we have at the moment is kind of a long battle with this virus to try to keep total morbidity and mortality as low as possible without disrupting society too much.”