Covid-19 case numbers remain high in the UK. In this article, I discuss why this is and why vaccines are working as expected, and protecting us from serious illness and death.
What is a breakthrough infection?
No vaccine is 100% effective against preventing infection.
An infection in a fully vaccinated person is sometimes described as a
breakthrough infection because the infective agent has “broken through” the
protection from infection provided by the vaccine.
How common is Covid-19 infection in fully vaccinated people?
Data from Public Health England show that the Covid-19 vaccines
used in the UK reduce the risk of infection
by about 70-90% in people who are fully vaccinated, so vaccines prevent the
majority of people who are vaccinated from becoming infected. However, some
people who are fully vaccinated will still become infected. Over time, as the
number of people in the population who are vaccinated increases, a greater
proportion of infections will occur in vaccinated people. It is possible that
the immunity from vaccination will weaken over time, with breakthrough
infections therefore becoming more common, which is why the government is now considering
giving booster doses of vaccine to some people.
How serious is Covid-19 infection in vaccinated people?
Research shows that vaccines are very effective in reducing
the risk of serious illness from a Covid-19 infection, with around a 95%
reduction in the risk of hospitalisation and death. However, some people who
are vaccinated will still have a serious illness. As with infections in
unvaccinated people, the risk of a serious illness is highest in the elderly
and people with medical problems such as diabetes and obesity.
What makes a breakthrough infection more likely?
The more people you come into close contact with, the more
likely you are to have a breakthrough infection. People whose work involves a
lot of contact with other people, such as health professionals, will be at
greater risk of a breakthrough infection. The risk of a breakthrough infection
is also higher in people with weak immune systems because vaccines work less
well for them. The risk of becoming infected with Covid-19 is highest in
poorly-ventilated, crowded indoor spaces. To reduce your risk of infection, you
should as far as possible, avoid these kinds of settings. A face mask can provide
some protection from infection, particularly if you use a higher specification
mask such as FFP2 mask.
How do new variants like delta effect the risk of infection?
The delta variant of the coronavirus that spread across the world
in 2021, and which is now responsible for nearly all cases of Covid-19 in the
UK, is more infectious than other variants. Vaccines will be a little less
effective at preventing infection from the delta variant than the variants that
were previously circulating in the UK. However, vaccines still remain very
effective at preventing serious illness, hospitalisation and death, even
against infections caused by the delta variant. So far, we have not yet come
across a variant of the coronavirus against which vaccines are ineffective.
How well are vaccines working in the UK?
Vaccines are working very well in the UK. Around 81% of
people aged 16 and over have been fully vaccinated. Public Health England
estimates that around 24 million infections, 144,000 hospitalisations and
112,000 deaths have been prevented by vaccination. Without vaccines, the number
of cases, hospitalisations and deaths in the UK would be much higher than now,
requiring further Covid-19 restrictions and lockdowns to control the pandemic.
It is vaccines that have allowed the government to relax these restrictions and
let people to live more normally.
First published in the Daily Mirror.
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