More than two years into the global Covid pandemic, it's incredible to think that some Irish people have never caught the virus.
It first hit Irish shores in March 2020 and is still with us today, with another wave rapidly spreading.
The latest date from the Health Protection Surveillance Centre shows 10,435 new weekly cases were confirmed - an increase of 52.6% compared to the previous week.
More than 1.6 million Covid cases have been confirmed in Ireland since the start of the pandemic, meaning there are many who have never caught the virus.
Scientists are now trying to work out why some people have, seemingly, never had Covid, with several major international studies underway to find out what the magical spell is that means they dodge it.
Dr Tara Hurst, a Lecturer in Biomedical Sciences at Birmingham City University is among them.
She told Birmingham Live that she's aware of the "Covid lottery".
"There is a population who say they've never had Covid and then are those poor souls who've had it several times," she said. "It is a very complex area which is now attracting a lot of research."
So why have some people never had Covid?
They've had Covid but didn't know it
Dr Hurst said a large number of people who claim to have never had Covid probably have had it. "There's a high chance they had it but didn't have any symptoms," she said.
"I'd say that between 45 to 90 per cent of people who think they've never had it actually have, but were asymptomatic."
She said one study had found that 45 per cent of people who tested positive actually had no symptoms.
They thought it was just a cold
There's another group of people who did have Covid but just dismissed it as a cold. This is because as the pandemic continued, the list of symptoms changed.
Dr Hurst said: "Not everyone had a cough or lost their sense of smell and taste. As the different variants arrived, so did the different symptoms and many sufferers would have just shrugged off their Covid, saying, it's just a cold."
Not everyone gets tested
Another factor is testing, which was crucial for gauging the official rates in the population. Some people because of their jobs (for example, teachers and healthcare workers) had to be tested regularly, others have never taken a test and if they did, only did an antigen, which isn't as reliable as a PCR.
They're genetically different
Dr Hurst said there's also a very special - but small - group of people who have never had Covid and haven't been vaccinated. This could be down to luck, but it's more likely there's something going on with their genetics which makes them resistant to viruses such as Covid.
"These people are very rare indeed and there's something going on with their bodies which means they can get the virus but it doesn't affect their cells, which means they don't actually develop Covid," Dr Hurst said.
Their 'negative' test was wrong
As the pandemic continued, the most common way to find out if you had Covid was doing an antigen test. All people had to do was swab their nose and throat and then wait a short time for the results. But antigen's weren't as reliable and accurate as the more uncomfortable PCR tests.
Some medics said antigens were only 40 per cent accurate - which means millions of people who had a 'negative' result could in fact have been positive.
They're super healthy
Dr Hurst said those who had not had any Covid symptoms, or never caught it, could be regarded as "super healthy". But it's more likely they have a more robust immune system
"This could be down to their genetics, but essentially they have an immune system which is super strong and fights the virus," she said. "They will have good general health, with factors such as good levels of Vitamins C and D. Stress is also a huge factor in this, as high levels of stress can have a negative impact on the immune system."
They behave differently
The way you live and behave can have a big impact on whether you fall prey to Covid. Measures such as wearing a mask when out in public, avoiding large crowds, getting vaccinated and not getting too close (in proximity) to strangers are said to reduce your chances of getting the virus.
Just like the common cold, if you live in the countryside and don't come into close contact with people very often, then you're less likely to get it.
Does this mean they'll never get Covid?
The answer is, nobody knows. Dr Hurst said: "I would say to those who've never had it - thank your lucky stars!"
Going forward, infections are starting to creep up again and there could be another wave in the autumn and winter and new variants are likely. Dr Hurst said: "Providing you've been vaccinated, the rest is down to common sense and being sensible."
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