Jeffries says surveillance is detecting flu, the SARS-CoV2 Covid virus, common cold viruses rhinovirus and adenovirus, and RSV.
The change in seasons can feel sudden – does this contribute to the increased levels of sickness?
“It’s quite complex, but it’s a mixture of what people have planned in their social calendars – and some of that is influenced by the weather – and work and school holidays affect it as well,” Jeffries says.
While several viruses are being detected, Covid-19 is currently “the main one of interest”, she says, though it’s common to see both a summer and a winter increase in cases.
How do I know what virus I have?
Epidemiologist Michael Baker says it can be tricky to tell if you have a cold, the flu or Covid-19, as “most of the symptoms do overlap”.
Common symptoms of Covid-19, flu, the common cold and RSV include a cough, sore throat and a runny or stuffy nose.
Brain fog is one distinct feature of Covid-19, as is the loss of taste and smell.
“Four of the viruses that cause the cold are coronaviruses, so [that effect on smell and taste] is one of the only features that’s really distinctive to coronaviruses.”
What is the ongoing impact of Covid-19 in New Zealand?
The winter cold and flu season lasts about six months – from April to September, while Covid-19 is still a “novel infection” in humans and is yet to settle into a seasonal pattern.
“It’s … causing two waves a year, and it’s not seasonal. These waves, if anything, have occurred more often in the warmer six months of the year than the colder six months,” Baker says.
“It may eventually settle into a more predictable pattern, it’s possible it will become seasonal, but we just don’t know how long that will take.”
Before Covid-19, influenza was the most serious infectious disease in New Zealand, killing on average 500 people a year and causing 1% of all deaths annually. Now, Baker says, Covid-19 kills about 1000 people a year in New Zealand, “and it’s still putting a lot of people in hospital”.
Hospitalisations with, and deaths from, Covid-19 are “skewed to older age groups”, Baker says, but long Covid affects people of all ages and can have a disabling effect.
“We need to be very concerned about long Covid … every infection you get, you are running that risk of getting long Covid.”
Long Covid cases aren’t being monitored in New Zealand, partly because it looks a little different for each person.
“We’ve got no surveillance of long Covid, and I think that’s a real gap. Many countries are doing this well,” Baker says.
“There isn’t a perfect case definition. Unless you’re tracking people over time, it’s quite hard to identify that change from normal functioning to developing long Covid.
“But there’s certainly so many people around anecdotally who are affected by this, and quite disabled by it. There’s no question about the phenomenon. There’s a vast literature on it. It’s just we’re not really counting it properly.”
What is the ‘super-K’ flu?
General Practice New Zealand chairman Bryan Betty says there is a new flu strain in New Zealand that is likely to affect more people in winter.
Influenza A subclade K, known as “super-K”, went around Europe and the US last year. Betty says it is currently circulating in New Zealand and Australia.
“The flu levels at this point are no worse than they normally are. However, the problem is because it’s in the country, once winter comes and people are congregating indoors, where we tend to spread viruses, it will suddenly pick up,” he says.
“We’ve got a Covid surge at the moment, we’ve got our normal cold viruses running around. That and potentially low immunisation rates for flu could be a recipe for a very difficult winter.”
The new variant is highly transmissible and potentially severe, particularly for elderly people. Symptoms include muscle ache, headache, a temperature, often a sore throat and cough, and it can be associated with nausea and vomiting.
How to protect yourself from flu, Covid-19 and other viruses
Vaccination is available for Covid-19 and influenza, while a vaccine for RSV is being investigated in New Zealand.
The flu vaccine will mitigate the severity of symptoms, and is particularly important for people aged over 65, those with comorbidities like diabetes or cardiovascular disease, pregnant women and young children.
Self-isolation and testing are also key, Baker says. You can now get a four-component RAT from pharmacies, though these are no longer subsidised by the government. Most cost about $10 and test for influenza A and B, RSV and Covid-19.
“Now if you’re not positive for Covid, you can see right away that you’ve got influenza, which can actually be a much worse experience.”
Another tool is ventilation, particularly as most of us spend our days in enclosed spaces – schools, offices, public transport – sharing air with lots of other people.
“It only takes one person there to have a respiratory infection and they can infect half the people in the room in half an hour or so,” Baker says.
“Any situation where you are exposed, particularly if it’s winter and you’ve got respiratory infections, say ‘Can I open a door, window, get a bit of a breeze happening’.”
An N95 mask can also stop aerosols, while surgical masks aren’t quite as effective at this.
“And the fantastic thing about masks is they work on all these viruses, it doesn’t matter what it is.”
Bethany Reitsma is a lifestyle writer who has been with the NZ Herald since 2019. She specialises in all things health and wellbeing and is passionate about telling Kiwis’ real-life stories.