MILLIONS of Brits have now received two doses of a vaccine that protects against Covid-19.
But even if you are vaccinated, you can still catch the coronavirus as no jab is 100 per cent effective.
Over 48.4 million Brits have had a first dose with over 44 millions having had two doses of either the Pfizer/BioNTech jab, the Oxford/AstraZeneca or the Moderna vaccines.
Just two weeks after your second dose, your protection will be at its highest level.
Experts previously found that even if you’re unfortunate enough to catch Covid after having both jabs then your symptoms will be less severe.
The vaccines have been proven to reduce your risk of death and serious illness from Covid-19.
Around 0.2 per cent of the population (one in 500) have a infection once vaccinated, a previous study in the Lancet found.
Booster jabs are soon to be rolled out and it was today announced that kids 12 and over will get coronavirus jabs in days, after experts said the ‘benefits outweigh the risks’.
Researchers at the University of East Anglia say there are different things that contribute to how well you respond to vaccines.
Writing in The Conversation, senior clinical lecturer, Vassilios Vassiliou, clinical fellow Ciaran Grafton-Clarke and researcher Ranu Baral have revealed the four things that mean you’re more likely to catch Covid despite being double vaccinated.
1. Type of vaccine
There are three types of vaccines having been given out in the UK and the experts said it’s all about the relative risk reduction that each one offers.
They explained: “Relative risk reduction is a measure of how much a vaccine reduces the risk of someone developing Covid-19 compared to someone who didn’t get vaccinated.
“Clinical trials found that the Moderna vaccine reduced a person’s risk of developing symptomatic Covid-19 by 94 per cent, while the Pfizer vaccine reduced this risk by 95 per cent.
“The Johnson & Johnson and AstraZeneca vaccines performed less well, reducing this risk by about 66 per cent and 70 per cent respectively (though protection offered by the AstraZeneca vaccine appeared to rise to 81 per cent if a longer gap was left between doses).”
2. Time since jab
You have the most protection two weeks after your second jab – but some research has suggested that efficacy can wane over time – which is why booster jabs are set to be rolled out across the UK.
The experts said: “Early research, still in preprint (and so yet to be reviewed by other scientists), suggests that the Pfizer vaccine’s protection wanes over the six months following vaccination.
“Another preprint from Israel also suggests that this is the case. It’s too soon to know what happens to vaccine efficacy beyond six months in the double vaccinated, but it’s likely to reduce further.”
As viruses are in circulation longer, they mutate – this is completely normal.
But as seen with the Alpha and Delta variants – some variants spread more easily across the community.
“When facing the alpha variant, data from Public Health England suggests that two doses of the Pfizer vaccine is slightly less protective, reducing the risk of getting Covid-19 symptoms by 93 per cent.
“Against delta, the level of protection falls even further, to 88 per cent. The AstraZeneca vaccine is also affected this way”, the experts said.
Non-government studies and data also back this up, with the experts at the Covid Symptom study stating that in the two to four weeks after receiving your second Pfizer jab, you’re around 87 per cent less likely to get Covid-19 symptoms when facing delta.
After four to five months, that figure falls to 77 per cent.
What are the variants and their scientific names?
- Kent/B.1.1.7: Alpha
- India/B.1.617.2: Delta
- South Africa/B.1.351: Beta
- Brazil/P.1: Gamma
- Brazil/P.2: Zeta
- India/B.1.617.1: Kappa
- Philippines/P.3: Theta
- California/B.1.427/B.1.429: Epsilon
- New York/B.1.526 – Iota
See more on the WHO website.
4. Immune system
The reason jabs were given to the most vulnerable and elderly at the start of the pandemic is because they usually have weakened immune systems.
The experts explained: “Our own risk will depend on your own levels of immunity and other person-specific factors (such as how exposed you are to the virus, which might be determined by your job).
“Immune fitness typically reduces with age. Long-term medical conditions may also impair our response to vaccination.
“Older people or people with compromised immune systems may therefore have lower levels of vaccine-induced protection against Covid-19, or may see their protection wane more quickly.”
They added that most vulnerable people received their jabs around eight months ago – so efficacy would now be waning – making them more susceptible to infection.
The experts said that the need for booster shots should not be interpreted negatively.
“Other countries, including France and Germany, are already planning on offering boosters to groups considered to be at higher risk from Covid-19.
“But even boosters end up being used, this shouldn’t be interpreted as vaccines not working. And in the meantime, it’s essential to promote vaccination to all those eligible who have not yet been vaccinated”, they added.
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