Covid 19: If we’ve all been jabbed why are we still being poleaxed by the virus

It began with a headache and sore throat one morning at the end of June. Then came a heavy chest that made breathing a struggle, while the headache became so bad that 66-year-old Mio Blagojevic describes it as ‘like having an out-of-body experience’.

The property developer from Hertfordshire adds: ‘I’d never felt so ill. It was like I’d been hit by a bus.’

With symptoms like these, this time last year the instant suspicion would have been Covid. But Mio, a keen runner, and his wife Karen had been fully vaccinated and then boosted in January.

Due to the severity of Mio’s symptoms, even the GP they called for advice did not suspect it could be Covid. They prescribed antibiotics, concluding that it was probably a bacterial chest infection.

Just to be sure, Mio took a lateral flow test. It was positive.

He recalls his shock: ‘We’d been quite careful for most of the pandemic, wearing masks and avoiding many big events. But I was pretty confident that, if I did get it, I would be fine because I’d had my jabs. But I couldn’t get out of bed for days and it took almost a month for me to fully recover.’

Mio also suffered a total loss of smell for a month – a symptom that characterised the first Covid waves but which research had suggested didn’t hit people infected with the less severe Omicron variant.

Meanwhile, Karen, who caught the virus at the same time, suffered no more than a headache. The whole episode left Mio shaken – and baffled.

It seems that he isn’t the only one in this predicament. Last week, The Mail on Sunday’s resident GP columnist, Dr Ellie Cannon, wrote that while some of her older patients, previously at risk of falling seriously ill with Covid, had become infected and simply brushed it off, she was seeing an increasing number of fit and healthy people struck down with ‘the worst flu ever’.

Since then she has received a flood of letters and emails from readers who had, like Mio, also been completely and unexpectedly poleaxed by the virus.

Susan Smith, 68, says she caught Covid three weeks ago, and despite having had three jabs she describes the illness as ‘the worst thing I can remember having’.

Her throat was so sore it felt ‘like I had razor blades’ in it. She lost her sense of taste and smell and felt extremely fatigued.

Susan believed a 78-year-old friend gave her the virus after he returned from Spain. However, he barely had any symptoms at all.

Alison Peek, a 64-year-old nurse, said her bout of Covid – her first despite working in a nursing home during the pandemic – left her in bed for ten days.

Fully vaccinated and boosted, Alison says: ‘The muscle fatigue I experienced was immense. I have never endured anything like it. It wasn’t just tiredness. It felt like I was wading through quicksand.’

This all begs the question: why, more than two years after Covid first appeared, are so many of us suddenly being laid so low?

Experts agree that the decision to offer all adults a third jab last winter, in response to the arrival of the highly transmissible Omicron variant, was a success. The reintroduction of Covid restrictions were avoided, and despite infections rising to record highs, the number of people hospitalised and dying with the virus stayed extremely low.

In the spring, over-75s were offered a fourth top-up jab. And this autumn, all Britons over the age of 50 will receive another dose in preparation for the winter.

In terms of vaccination, we are among the most protected in the world. However, there is still a lot of Covid around.

While cases are now falling from a peak in mid-July, more than two million Britons have the virus. There are also several new sub-variants driving infections.

Since the spring, two mutated versions of Omicron have been the cause of most cases in the UK. Labelled BA.4 and BA.5, they appear to cause some different symptoms to their predecessor.

According to the King’s College London Zoe symptom tracker app, anosmia – loss of sense of smell – is often reported. Its analysis suggests that more people are experiencing sore throats, as well as a previously uncommon symptom: diarrhoea.

These mutations can also overcome the immunity built up by vaccines and prior infection. It means someone who caught Covid in May could easily catch it again if exposed now.

Scientists say that with so many people infected, it stands to reason that statistically, while most can shrug off the virus thanks to protection provided by the jabs, some will still get hit badly. And a few will end up in hospital, even if they have been vaccinated.

‘Thanks to vaccination, Covid is now essentially acting as two different diseases,’ says Professor Paul Hunter, an infectious diseases expert at the University of East Anglia (UEA).

‘When the virus first arrived, doctors were most concerned about systemic infections – where the virus can get into your lungs and lead to pneumonia.

‘This is what usually kills patients. But we’re not seeing anywhere near as much of this.

‘Instead, most people are experiencing an upper respiratory tract infection, which means it’s their noses and throats affected, and it doesn’t get into their lungs. This is much like any standard cold and flu.’

But Prof Hunter also points out that regular colds and flu do floor otherwise healthy people.

‘It’s perfectly normal to see someone in their mid-20s get flu really badly to the point where they are in bed for a week. Their friend who got the same virus might be absolutely fine.’

He adds: ‘In reality, if you caught flu now you’d be more likely to get seriously ill than you would with Covid. This is because there has been very little flu, meaning few people have any immunity.’

Worryingly, scientists believe we are now due a bad flu season.

Australia – seen as a bellwether, as its winter occurs during our summer months – has suffered its worst flu season for five years.

Last month, the Government announced that everyone over 50 would be offered a flu shot with their Covid booster in September. It will also be available to people with underlying health conditions, pregnant women, healthcare workers and carers, as well as secondary school children.

But putting this aside, is there a way to predict who might get a bad case of Covid?

Experts say the most crucial factor is when people had their last booster.

‘On average, the extra vaccine gives you only three months’ protection from infection,’ says Professor Lawrence Young, a virus expert at the University of Warwick. The good news is that scientists are certain the vaccines we have had will continue to provide most of us with protection against severe illness needing hospital treatment.

Vaccines create antibodies which prevent the virus entering the body, but they also encourage the production of other protective immune cells – including T cells, which attack invaders before they can do too much damage.

‘T cell response still looks really solid,’ says Prof Young. ‘But as your antibodies wane, more virus can get in, so your risk of getting a nasty yet non-threatening infection goes up.’

And since the over-75s had a booster jab in the spring, experts say this age group is, in fact, less likely to get very ill.

Figures published last week by the Office for National Statistics appears to back this up.

According to a survey of UK antibody levels, more than 90 per cent of people over the age of 75 – those who had received a second booster – have a high level of antibodies. However, just 60 per cent of those aged between 65 and 74 had similar levels.

‘If you’re in your 40s, your last jab will have been a lot longer ago than if you’re in your 70s,’ says Prof Hunter.

‘So it stands to reason the risk of the 40-year-old getting laid out badly may actually be higher.’

One 40-year-old who knows this all too well is Kristian Jenson, from London, who caught the virus for the first time last month.

The vintage furniture seller had his third jab in December, and says while he expected to catch Covid eventually, he never expected to become so unwell. He adds: ‘I had the worst headache, I was coughing loads and lost all my sense of smell and taste.

‘I’d had my booster and I’m relatively young and healthy, so I thought I’d be able to brush it off after a couple days. It was so bad I had to take two weeks off work, and I’m still recovering five weeks on.’

Kristian will not receive another Covid jab soon, since only over-50s will be offered one this winter. This makes him nervous as he worries about catching the virus again.

He says: ‘It was really tough physically, but also financially because I had to take time off work, and then there’s childcare as we had to keep our son home. It makes life really tricky when you get this ill.’

Scientists say there are other factors which determine the severity of Covid infection. Multiple studies show that men are more likely to suffer worse symptoms than women, which may in part explain why Mio suffered worse than his wife.

‘Male immune systems tend to react more slowly to viruses,’ says Prof Young.

Experts believe genetics play a role in the infection’s severity.

A German study, published last year, found that people with the blood type O – the most common group – had a heightened protection against severe Covid compared with the national average. People with the less common blood type A were noticeably more likely to get dangerously sick, though scientists are unsure why.

Scientists also believe the amount of Covid particles someone is exposed to when they become infected could also determine how sick they get.

‘If you get Covid after spending several hours sitting next to someone with the virus in an office with poor ventilation, you’re probably going to get more sick than someone who picks up the virus after chatting with someone for two minutes,’ says Prof Hunter.

Having had a recent cold reduces the severity of a Covid infection. This is because most colds are also forms of coronavirus – closely related to Covid and similar in structure.

So when the immune system develops cells to fight off a cold, these cells can put up defence to Covid.

An American study, published last week, suggested that people who had suffered a cold as a result of infection with another coronavirus in the previous three months were far less likely to catch Covid.

Regardless of this, experts say we have to expect several more years of regular waves of Covid.

Professor Peter Openshaw, an immunologist at Imperial College London, says: ‘People are still being reinfected because the virus is mutating to evade our immunity.

‘So even though the vast majority of Britons have really high levels of antibodies, they’re still liable to get quite sick with the virus, even if they’re not as likely to end up in hospital.’

The good news, according to Prof Openshaw, is that the virus cannot continue keep evolving at this rate.

‘The virus is essentially evolving under pressure. It’s reacting to the vaccines and the build-up of previous infections, in an effort to survive,’ he says.

‘But eventually, probably in about three years, it will settle down into something more akin to the common cold.’