A loss in the sense of taste and smell paired with a persistent cough were among the top symptoms Australians were urged to watch out for in the early days of the COVID-19 pandemic.
Experts are now telling people to pay attention to more subtle signs, such as a runny nose, as new virus strains such as the Delta variant change the way symptoms present in patients.
Burnet Institute epidemiologist Michael Toole said data collected in Britain showed symptoms displayed by patients sick with the more contagious strain of the virus differed from those of other variants.
The information, collected through the app-based ZOE COVID symptom study, which allows users to log their symptoms, suggested the variant felt more like a bad cold than coronavirus.
The most commons signs for those fully and partially vaccinated included a headache, runny nose, and sneezing, followed by a sore throat.
For those not vaccinated, it also included fever.
A persistent cough, shortness of breath, and fever – common symptoms of earlier variants – were relegated further down the list in terms of prevalence among patients.
With winter in full swing and several major Australian cities in lockdown due to fears of a Delta variant outbreak, Professor Toole said it was essential people didn’t disregard the symptoms as a normal cold.
“In winter, we’re all used to having a runny nose, a cold. But now, people should all be aware that a runny nose may not be the common cold; it may be COVID,” he said.
“That really changes it a bit because those symptoms are not very dramatic.”
The change in symptoms is believed to be the result of mutations in the virus, higher vaccination rates, and a larger proportion of cases involving young people, which show less severe symptoms.
The Delta variant – formerly known as B1.617.2 – was first recorded in India and is one of two sub-variants of the B1.617 lineage. The other is the Kappa variant, which was behind the Melbourne lockdown in May.
Evidence suggests it is substantially more transmissible than the Alpha variant, which was already more transmissible than the virus that was first recorded in Wuhan.
Millions were locked down in cities across Australia on Wednesday morning after four states implemented stay-at-home orders to contain the spread of the virus.
Queensland recorded three new cases in the community as it entered the first day of a three-day snap lockdown prompted by a 19-year-old unvaccinated hospital worker who tested positive for the virus after being infectious in the community for 10 days.
In Western Australia, the Perth and Peel regions were plunged into a four-day lockdown on Monday night, amid fears a physiotherapist who recently returned from Sydney could have infected several people with the Delta strain. To date, two people have tested positive for the virus but test results for hundreds of close contacts are still pending.
Parts of New South Wales, including Greater Sydney and Central Coast, remained locked down on Wednesday as the state recorded 22 new local coronavirus cases in 24 hours. Half of the new cases were in isolation for their entire infectious period but five were only in quarantine for a portion of that time.
The Northern Territory extended restrictions for Darwin, Palmerston, and the rural area for another 72 hours on Wednesday after a COVID cluster linked to a Tanami gold mine grew to seven cases. An initial lockdown was implemented on Sunday after a fly-in fly-out worker at the Granites mine site tested positive for the virus last Friday.