Why experts are worried about the Covid booster uptake

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Hello, and welcome back to i‘s science and tech newsletter. Over the coming weeks there will be a series of guest newsletters that will try and untangle big issues affecting the twinned worlds of science and technology. I’m Tom Bawden, science and environment correspondent at i. This week, we’re looking at the effectiveness of the Covid booster.

The issue is in the news because the Autumn booster campaign will finish at the end of the month, meaning that those who are eligible still have a week to get their jab – or else they will have to wait until September or October for another chance. At the same time, there happens to have been a number of key reports on vaccine effectiveness this month.

Covid rates may be coming down but there were still 1.3 million people, or 1 in 43, infected in England and Scotland at the last count in mid-January. At the same time, while the virus may be less severe than it was, it can still lead to serious illness and death, especially in the vulnerable populations eligible for the booster.

Yet even in the most at-risk groups of 75 and over only about 75 per cent have taken up the vaccine this booster campaign, while the uptake in the 65 to 69 age group is only 60 per cent, according to the UK Health Security Agency (UKHSA). But scientists pretty much unanimously agree that the best – and probably now only – way to reduce the risk of serious illness and hospitalisation is vaccination.

The two best sources on the benefit of vaccination to the individual are probably the UKHSA and a systematic review of 26 previous studies published in The Lancet last week.

What they tell us is that Covid vaccines and boosters are pretty good at preventing an infection in the first place – although the benefit falls away quite quickly. But what they are really good at is protecting against severe illness if you do get infected, which is its main task.

The Lancet study tells us that a booster cuts the risk of infection by 75 per cent in the first month or so, falling to 50 per cent after three months and about 20 per cent after eight months.

But when it comes to serious illness and hospital admissions, the protection is much bigger and more sustained. Here, the booster reduces the risk by about 90 per cent for the first few months and is still around 75 per cent lower after eight months, according to the study, which was led by Calgary University in Canada and also involved University College London.

Meanwhile, the UK Health Security Agency’s last surveillance report to look at vaccine effectiveness – published in January 2023 and relating to the spring 2022 booster campaign – also found boosters to be very good at keeping people out of hospital.

The jab reduced the risk of hospitalisation in all over 18 age groups in the first few weeks by 92.4 per cent, it found.

And after 39 weeks, 18 to 65 year old’s who had had it were 53.7 per cent less likely to be admitted to hospital, compared to 66.8 per cent of over 65s.

When it comes to the broader good that vaccines have done (for the population as a whole), another two new studies are key.

The first, published in The Lancet last week, found that 7,180 hospitalisations and deaths could have been avoided in the UK in the summer of 2022 alone had the whole population taken up all the doses they were eligible for. That would have cut hospitalisations and deaths – which were 40,393 between June 1 and September 2022 – by nearly a fifth.

That study, the first to involve the entire UK population of 67 million people, also found a low uptake of vaccines, even at this point – with just 44 per cent of the population having had had their recommended number of jabs and boosters by June 2022, according to the study, led by Health Data Research UK (HDR UK) and the University of Edinburgh.

Another new study, by the World Health Organisation, estimated that jabs saved 396,532 lives in England and 24,340 lives in Scotland between December 2020 and March 2023, the first 26 months that they were available – with the total number now likely to be thousands higher. As such, vaccines cut the death toll by 70 per cent in England and Scotland over that period, the analysis concludes.

And for Europe as a whole, vaccines saved around 1.4 million lives, or 57 per cent, according to the study, which was led by The WHO European Respiratory Surveillance Network and included researchers from the UK Health Security Agency (UKHSA) and Public Health Scotland, which is published on the medRxiv server ahead of peer-review by other scientists because of its timely nature.

The other big benefit of vaccines are in reducing the risk of developing long Covid, in which symptoms persist for 12 weeks or longer and can often continue for a year or two, and even longer.

A study published in the journal Lancet Respiratory Medicine this month analysed more than 20 million vaccinated and unvaccinated people in the UK, Estonia and Spain and found that vaccines reduced the risk of developing long Covid by between a third and a fifth.

“Vaccination against Covid-19 consistently reduced the risk of long Covid symptoms, which highlights the importance of vaccination to prevent persistent Covid-19 symptoms, particularly in adults,” concluded the study, led by Oxford University.

This is thought to be the first multi-national study looking at the whole population rather than just those who got long Covid meaning that, unlike those studies, it included “the effect of vaccines to prevent infection as part of the pathway to developing post-Covid 19 complications.”

In the light of the effectiveness of vaccines, Professor Steven Riley, Director General for Data and Surveillance at UKHSA urged anyone who has been offered a booster, and not taken it up, to get one while there is still time.

“Those people who are most at risk of severe illness from COVID-19 can still come forward for their seasonal vaccination until 31 January 2024. You can get a vaccine through your GP, by booking with a local NHS vaccination service, or you can find a COVID-19 vaccination walk-in site.”

You are eligible for a COVID-19 vaccine if you are: 

• aged 65 years or over (by 31 March 2024)
• aged 6 months to 64 years and are at increased risk
• living in a care home for older adults
• a frontline health or social care worker
• aged 16 to 64 years and are a carer
• aged 12 to 64 years and live with someone with a weakened immune system

There have been reports that Covid vaccines can lead to heart and other serious problems, but scientists say any potential risk is far outweighed by the benefits.

In a study published last January, Vahé Nafilyan, Senior Statistician, Office for National Statistics, concluded that: “Whilst vaccination carries some risks, these need to be assessed in light of its benefits. Our analysis shows that the risk of death is greatly increased following a positive test for Covid-19 even in young people and many studies show that vaccines are highly effective at preventing hospitalisation or death following Covid-19 infection.”

Meanwhile, according to the NHS, most side effects of the vaccine are mild and should not last longer than a week. They include:

• a sore arm from the injection 
• feeling tired 
• a headache 
• feeling achy 
• mild flu-like symptoms
• feeling or being sick 

This is i on Science, a subscriber-only newsletter from i. If you’d like to get this direct to your inbox, every single week, you can sign up here.