The BA.2 subvariant of Omicron has quickly become the dominant strain of Covid-19 in New Zealand. What is it and what impact will it have on the current outbreak? RNZ is here to clear it all up.
Over time viruses change and mutate, creating new variants and subvariants. As we know, there are a number of variants of Covid-19, each given their own letter of the Greek alphabet like Beta, Delta and Omicron. BA.2 is one of several subvariants of the Omicron variant of Covid-19 – not quite unique enough to be given its own letter, though whether it should still have one is debatable.
When you think about Omicron, until now it was likely you’re thinking about BA.1, which was dominant in most Omicron outbreaks until recently. BA.1 and BA.2 have differences in genetic sequence, including amino acids and proteins.
BA.2 was first detected in November 2021, around the same time as BA.1 but by mid-March 2022, BA.2 was rapidly gaining momentum around the world.
First found in New Zealand in late-January when a number of border workers and close contacts tested positive, as of mid-March, nearly 80 per cent of recent cases that had undergone genomic sequencing here were found to be the BA.2 subvariant.
Though with rapid antigen tests now the dominant form of testing in New Zealand, genomic sequencing is less common than it once was and so it is impossible to know just how widespread a variant is at any one time.
It’s highly unlikely you will know whether you’ve tested positive for BA.1 or BA.2 if you’ve tested positive for Covid-19.
Director general of health Dr Ashley Bloomfield says the prevalence of BA.2 was part of the reason why case numbers in Auckland during the peak of the Omicron outbreak were higher than modelling predicted.
Health officials in England reported the vaccine was similar in effectiveness against symptomatic disease for both BA.1 and BA.2. Photo / Michael Craig
What does this mean for the Omicron outbreak?
While it may prolong the Omicron surge, it’s unlikely the rise in BA.2 cases would result in a large second wave as some countries are dealing with, Otago University virologist Dr Jemma Geoghegan told Morning Report.
In fact, she says, seeing a rise in BA.2 at the same time as BA.1 is the best possible scenario and having this happen at the end of summer and among a highly vaccinated population was an advantage too.
Bloomfield says if the majority of cases in New Zealand’s outbreak were BA.2 it could act in the country’s favour.
He says some places such as New South Wales, the UK and particularly Scotland – were seeing second outbreaks with the BA.2 subvariant, having already had BA.1 subvariant outbreaks.
“Even those jurisdictions that had an initial quite big Omicron outbreak are getting a second one, that seems to be associated with the BA.2 subvariant.”
If most of New Zealand’s Omicron cases are already the BA.2 subvariant, Bloomfield says there is a chance “we will miss that second big peak again that other countries are seeing”.
That’s what has happened in Denmark, which saw a rise in BA.2 during its first Omicron wave.
Is it more transmissible?
It’s estimated BA.2 is up to 40 per cent more transmissible than the already highly transmissible BA.1.
A study of 8,500 households and 18,000 individuals conducted by Denmark’s Statens Serum Institut (SSI) found that BA.2 was “substantially” more transmissible than BA.1, though it’s important to note this has not yet been peer reviewed.
A separate UK study also found higher transmissibility for BA.2 compared to BA.1.
Data is still limited but the World Health Organisation says people have been reinfected with BA.2 after having had an infection of BA.1.
“Data suggests that antibodies from past BA.1 infection does give you some protection against BA.2, although clearly reinfections can happen, they’re probably more rare,” Geoghegan says.
It’s highly unlikely you will know whether you’ve tested positive for BA.1 or BA.2 if you’ve tested positive for Covid-19. Photo / Alex Burton
Is it more severe?
Bloomfield says while BA.2 is more transmissible, there is currently no evidence to suggest it is more or less severe.
A risk assessment report from Denmark’s SSI in late-February found there wasn’t an increased risk of hospital admission associated with BA.2 compared to BA.1. And that’s what researchers in England found too.
How effective are vaccines against BA.2 ?
Vaccines appear to effectively shield people against the highly transmissible BA.2, Geoghegan says.
“The real-world data suggests there’s no difference in disease severity between the two variants and the vaccine and boosters appear to be providing really good protection against both subvariants as well.”
Health officials in England reported the vaccine was similar in effectiveness against symptomatic disease for both BA.1 and BA.2.
Pfizer boss Albert Bourla told CBS the company is currently trying to make a vaccine that would protect against all variants, and last up to a year.
Both Pfizer and Moderna think a fourth dose of their Covid-19 vaccines – a second booster shot – is necessary as the protection from earlier doses wanes.
The BA.2 subvariant has quickly become the dominant strain of Covid-19 in NZ. Photo / Nik Dirga, RNZ
How is a new variant found?
PCR testing continues to be used in hospital settings and at the border as part of New Zealand’s surveillance regime, allowing officials to detect new variants in the country – this surveillance testing is how officials know BA.2 is on the rise here.
Prime Minister Jacinda Ardern wants New Zealand to become “really sufficient” at surveillance at the border, “gold standard,” she says.
Auckland University’s Dr David Welch says the border reopening has increased the need for better testing for the virus to guard against new variants.
Can we expect more variants (or subvariants) in the future?
New variants of Covid-19 pop up all of the time and have done since the beginning of the outbreak, whether of not they become a ‘variant of concern’ is decided by the World Health Organisation. The subvariants of Omicron are currently being monitored by WHO.
“With less stringent border restrictions we expect to see new lineages of viral genomes – genomics enables us to watch these closely,” the Institute of Environmental Science and Research’s principal scientist and genomics lead Professor Mike Bunce and lead bioinformatics and genomics, Dr Joep de Ligt say in a joint statement.
“Hospital cases are a priority for genome sequencing. The genomic surveillance plan also calls for multiple samples to be taken from patients that have a prolonged infection with Covid-19. The risk here is that the virus, if not ‘cleared’, can accumulate mutations; we can monitor this by taking samples over time and seeing if key parts of the virus (such as the spike protein) are changing,” they say.
“New variants can also emerge in long-haul (long Covid) patients, and there is an increasing awareness of this on the international stage.”
Dr Welch says MIQ gave New Zealand a “real time buffer and that time buffer has allowed us to plan to prepare”.
“If we can detect something at the border then you know it would still have to grow inside New Zealand and spread, so spotting at the border rather than once it’s already spread widely, could give us a … two or four weeks heads-up.”
The Canadian government says it will donate up to 200,000 vaccine doses to fight the mpox outbreak in Congo and other African countries.
It says the donated doses of Imvamune will come from Canada’s existing supply and will not affect the country’s preparedness for mpox cases in this country.
Minister of Health Mark Holland says the donation “will help to protect those in the most affected regions of Africa and will help prevent further spread of the virus.”
Dr. Madhukar Pai, Canada research chair in epidemiology and global health, says although the donation is welcome, it is a very small portion of the estimated 10 million vaccine doses needed to control the outbreak.
Vaccine donations from wealthier countries have only recently started arriving in Africa, almost a month after the World Health Organization declared the mpox outbreak a public health emergency of international concern.
A few days after the declaration in August, Global Affairs Canada announced a contribution of $1 million for mpox surveillance, diagnostic tools, research and community awareness in Africa.
On Thursday, the Africa Centres for Disease Control and Prevention said mpox is still on the rise and that testing rates are “insufficient” across the continent.
Jason Kindrachuk, Canada research chair in emerging viruses at the University of Manitoba, said donating vaccines, in addition to supporting surveillance and diagnostic tests, is “massively important.”
But Kindrachuk, who has worked on the ground in Congo during the epidemic, also said that the international response to the mpox outbreak is “better late than never (but) better never late.”
“It would have been fantastic for us globally to not be in this position by having provided doses a much, much longer time prior than when we are,” he said, noting that the outbreak of clade I mpox in Congo started in early 2023.
Clade II mpox, endemic in regions of West Africa, came to the world’s attention even earlier — in 2022 — as that strain of virus spread to other countries, including Canada.
Two doses are recommended for mpox vaccination, so the donation may only benefit 100,000 people, Pai said.
Pai questioned whether Canada is contributing enough, as the federal government hasn’t said what percentage of its mpox vaccine stockpile it is donating.
“Small donations are simply not going to help end this crisis. We need to show greater solidarity and support,” he said in an email.
“That is the biggest lesson from the COVID-19 pandemic — our collective safety is tied with that of other nations.”
This report by The Canadian Press was first published Sept. 13, 2024.
Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.
HALIFAX – The Nova Scotia government says it could be months before it reveals how many people are on the wait-list for a family doctor.
The head of the province’s health authority told reporters Wednesday that the government won’t release updated data until the 160,000 people who were on the wait-list in June are contacted to verify whether they still need primary care.
Karen Oldfield said Nova Scotia Health is working on validating the primary care wait-list data before posting new numbers, and that work may take a matter of months. The most recent public wait-list figures are from June 1, when 160,234 people, or about 16 per cent of the population, were on it.
“It’s going to take time to make 160,000 calls,” Oldfield said. “We are not talking weeks, we are talking months.”
The interim CEO and president of Nova Scotia Health said people on the list are being asked where they live, whether they still need a family doctor, and to give an update on their health.
A spokesperson with the province’s Health Department says the government and its health authority are “working hard” to turn the wait-list registry into a useful tool, adding that the data will be shared once it is validated.
Nova Scotia’s NDP are calling on Premier Tim Houston to immediately release statistics on how many people are looking for a family doctor. On Tuesday, the NDP introduced a bill that would require the health minister to make the number public every month.
“It is unacceptable for the list to be more than three months out of date,” NDP Leader Claudia Chender said Tuesday.
Chender said releasing this data regularly is vital so Nova Scotians can track the government’s progress on its main 2021 campaign promise: fixing health care.
The number of people in need of a family doctor has more than doubled between the 2021 summer election campaign and June 2024. Since September 2021 about 300 doctors have been added to the provincial health system, the Health Department said.
“We’ll know if Tim Houston is keeping his 2021 election promise to fix health care when Nova Scotians are attached to primary care,” Chender said.
This report by The Canadian Press was first published Sept. 11, 2024.
ST. JOHN’S, N.L. – Newfoundland and Labrador‘s chief medical officer is monitoring the rise of whooping cough infections across the province as cases of the highly contagious disease continue to grow across Canada.
Dr. Janice Fitzgerald says that so far this year, the province has recorded 230 confirmed cases of the vaccine-preventable respiratory tract infection, also known as pertussis.
Late last month, Quebec reported more than 11,000 cases during the same time period, while Ontario counted 470 cases, well above the five-year average of 98. In Quebec, the majority of patients are between the ages of 10 and 14.
Meanwhile, New Brunswick has declared a whooping cough outbreak across the province. A total of 141 cases were reported by last month, exceeding the five-year average of 34.
The disease can lead to severe complications among vulnerable populations including infants, who are at the highest risk of suffering from complications like pneumonia and seizures. Symptoms may start with a runny nose, mild fever and cough, then progress to severe coughing accompanied by a distinctive “whooping” sound during inhalation.
“The public, especially pregnant people and those in close contact with infants, are encouraged to be aware of symptoms related to pertussis and to ensure vaccinations are up to date,” Newfoundland and Labrador’s Health Department said in a statement.
Whooping cough can be treated with antibiotics, but vaccination is the most effective way to control the spread of the disease. As a result, the province has expanded immunization efforts this school year. While booster doses are already offered in Grade 9, the vaccine is now being offered to Grade 8 students as well.
Public health officials say whooping cough is a cyclical disease that increases every two to five or six years.
Meanwhile, New Brunswick’s acting chief medical officer of health expects the current case count to get worse before tapering off.
A rise in whooping cough cases has also been reported in the United States and elsewhere. The Pan American Health Organization issued an alert in July encouraging countries to ramp up their surveillance and vaccination coverage.
This report by The Canadian Press was first published Sept. 10, 2024.
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