Winter is upon us and so too are the season's ills, as a number of Covid-19 subvariants start to circulate.
A number of Omicron subvariants are in the community in Aotearoa: BA.1, BA.2, BA.4, BA.5 and BA.2.12.1.
On Friday, the first case of BA.4 and BA.5 (four cases) were reported in the community. BA.2.12.1 was also detected (seven cases) last week. The subvariants also showed up in wastewater across a handful of regions.
So what Covid-19 symptoms should you be on the lookout for, and do these differ between subvariants?
* Omicron NZ: I've had Covid! Can I get it again?
* Omicron subvariant BA.2.12.1 discovered in community, more subvariants in wastewater
* Why are there so many new Omicron sub-variants and will I be reinfected?
People with Covid-19 report a wide range of symptoms, ranging from being asymptomatic, to mild symptoms to severe illness. Common symptoms include:
- Fever or chills
- Shortness of breath or difficulty breathing
- Muscle or body aches
- New loss of taste or smell
- Sore throat
- Congestion or runny nose
- Nausea or vomiting
The ZOE Covid study, which records daily health reports from more than 4 million people worldwide, the top five symptoms reported by contributors with a positive Covid-19 test as of April (with Omicron dominant) were runny nose (83%), fatigue (71%), sore throat (69%), headache (69%), and sneezing (68%).
Symptoms such as fever and partial or full loss of smell were “much less common” since the Omicron variant emerged, Professor Tim Spector, lead scientist of the ZOE app earlier told the BMJ.
Epidemiologist, University of Otago (Wellington) Professor Michael Baker said Omicron subvariants tend to behave the same way in terms of symptoms.
While there are differences between the transmissibility of Omicron subvariants, so far, symptoms appear to be consistent with one another.
The presence and severity of Covid-19 symptoms can be affected by age, vaccination status, underlying health conditions, and history of prior infection.
‘Significant number’ of cases going unidentified
Meanwhile, detections of SARS-CoV-2 in wastewater have been trending upwards on the whole – a slight “decoupling” from what is being seen in daily RAT case numbers are showing, ESR’s principal scientist (genomics) Professor Mike Bunce said.
While there has been a trend in recent weeks of a “slight” increase in cases, cases this week had been trending down, the Ministry of Health told Stuff at this stage this “is not evidence of a second wave of Omicron”.
However, modelling suggests an increase in Covid-19 cases – alongside other respiratory illnesses – was likely over winter.
The move to self-reported RATs “has always meant there would be a significant number of Covid-19 cases that would not be identified” and captured in reporting, a ministry spokesperson said.
Reported case numbers and wastewater detections were expected to continue to fluctuate.
The vast majority of recently sequenced cases in Aotearoa continue to be BA.2, with BA.1 making up a small proportion of cases.
Emerging data suggests BA.2.12.1 is “marginally” more transmissible than BA.2.
There was also some clinical data suggesting BA.4 and BA.5 have increased transmissibility when compared to BA.2, but no data suggesting they cause more severe illness, the ministry says.