It seems like everyone has developed different Covid symptoms over the last two years, but the science behind it can tell us a lot about your immune response.
When the virus was first detected back in 2019, people who tested positive came down with a high temperature, dry, continuous cough and lost their sense of smell or taste.
Although the No.10 has only just allowed extra symptoms to be added to the official signs of Covid list – including headache, sore throat and blocked or runny nose – other organisations first noted these traits last year.
On top of that, there’s the confusing gap between when you develop symptoms and when you actually test positive, not to mention the phenomenon of asymptomatic people.
Here’s the explanation behind these particularly confusing elements of Covid.
So what does it mean if you lose your sense of smell?
US epidemiologist Dr Michael Mina explained on Twitter that the original Covid symptoms, including a loss of smell or taste and breathing problems, mean the virus is attacking you before your immune system kicks in.
He tweeted: “Symptoms can reflect that the virus is destroying your cells (loss of smell, difficult breathing...)”
What if you develop cold-like symptoms?
Mina noted that cold-like symptoms, which have become more common as the pandemic has progressed, usually show your immune system is fighting back before the virus can really take hold.
He tweeted: “Symptoms (cold-like) can reflect that your body’s immune system is attacking the virus before it grows high.”
Even back in June 2021, the ZOE Covid Study also noted that vaccinated people who tested positive were “more likely to report sneezing as a symptom compared with those without a jab”.
These vaccinated individuals will have an increased immune response due to the jab, even if they haven’t had Covid before.
As the ZOE study pointed out: “Vaccinated people experience the same kinds of symptoms as unvaccinated people do, but their illness is milder and shorter. We also know that more people have asymptomatic Covid-19 after their jab.”
It can vary from variant to variant too
The ZOE Covid study confirmed on Thursday that people infected with the Omicron variant usually have symptoms for a shorter period of time and are less likely to be admitted to hospital compared to Delta.
The findings suggested people suffering from Omicron were approximately half as likely to report having a fever, a cough, or a loss or change in taste or smell than Delta.
Omicron is believed to be better at evading the body’s immune response compared to Delta, but it also triggers a less severe disease – for instance, ZOE’s latest findings suggested Omicron symptoms lasted on average 6.9 days while Delta’s usually lasted 8.9 days.
However, Dr David Strain from the University of Exeter Medical School believes the situation has altered once more now the BA.2 strain of Omicron has emerged.
He said: “People in hospital are staying in hospital for longer and staff are testing positive for longer, so it is longer before they can return to work.”
So...what does this all mean?
Although different variants can cause different symptoms, epidemiologist Mina explained that it is still important to take note of which ones are affecting you.
As Mina explained: “It’s very important that we stop just saying symptoms as though they are all the same. They aren’t!
“If due to virus destroying your cells – then the symptoms start around peak virus load.
“If due to immune activation symptoms often start early before the virus grows high.”
Mina then referred to a graph explaining why, if you have a breakthrough infection, your immunity should recognise the virus quickly, which could trigger immune symptoms.
The virus might still infect you afterwards, but your symptoms have already “kicked in”, he explained.