How long after Covid booster are you immune?
EVERY adult in the UK can expect an NHS invite for their booster Covid vaccine in the next two months.
To tackle the new super mutant Covid strain Omicron, ministers are throwing "everything at it" - namely millions of booster shots.
Prime Minister Boris Johnson has pledged for all over 18s to get a top-up dose by the end of January 2022.
It will only be three months after your second Covid vaccine dose that the NHS will invite you for a third.
Many people will be wondering how long does the booster offer protection, if they are being rolled out so quickly after the second doses?
Here, we answer your questions.
How long after Covid booster are you immune?
It’s too early to say how long protection against Covid lasts after a booster.
After the primary two doses, antibodies start falling from around three months.
When announcing the advice to give boosters to older adults in September, the JCVI said: “Insufficient time has passed to know what levels of protection might be expected six to 12 months after the primary course.”
England’s deputy chief medical officer, Professor Jonathan Van-Tam, believes that protection from a booster lasts a little better than after only two doses.
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He told the BBC on November 3: “I think, on first principles, it’s quite likely that the third dose that you get, the booster dose, is likely to last a bit longer than the protection that we have from the first two doses, which is now starting to wane.
“But I can’t give you a straight answer to that because the truth of the matter is this is a new disease, we are still learning about it, we are still learning about how long these vaccines will last for after the third dose.
“And we have to wait for those data before we can give you absolutely emphatic answers.”
Research looking at the strength of immunity after vaccine doses only looks at antibodies.
But there are other parts of the immune system that are thought to be potent and last much longer.
After antibody levels fall, a small percentage of B and T-cells will stick around as “memory cells”. These can live for months, years and sometimes even decades.
Exactly how long they last after a Covid vaccine is not known because it has only been one year since the jabs started being rolled out.
But studies - and vaccine manufacturers - have claimed T-cell responses are strong and may be working to protect the elderly and vulnerable even when their antibodies dip.
How often will we need a booster?
Experts have said it’s possible that a Covid booster jab will be offered annually, like the flu jab, to drive protection back up.
It may also be that every year, there is a new virus strain that the vaccines need to be geared against.
Prof Van-Tam said: “Is there some kind of known issue about having to have repeat doses of vaccine?
“Well, no, there isn’t, and you can see that from the annual flu jab which is given year after year, decade after decade to the elderly, to people with high-risk conditions.”
The head of the NHS in England, Amanda Pritchard, has said the health service is preparing for the prospect of an annual Covid-19 booster vaccine programme – should one be required.
Professor Mike Tildesley, a member of the Scientific Pandemic Influenza Modelling group (Spi-M), has said that repeated vaccinations could be offered “for years to come” to keep Covid at a bay.
How much do boosters increase protection?
Adults aged 50 years and over have 93.1 per cent protection against symptomatic infection after two Oxford/AstraZeneca (AZ) doses.
This falls from 65 per cent, up to three months after the second dose, to 45 per cent six months after the second dose.
Those who had an initial course of Pfizer get protection of 94 per cent.
This falls to 90 per cent after three months to 65 per cent after six.
But after boosters (of which all are Pfizer), protection goes up to 93.1 per cent in those who first got AZ, and 94 per cent in those who had Pfizer.
Looking at hospitalisation, protection falls from 95 per cent to 75 per cent for AZ and 99 per cent to 90 per cent for Pfizer between three and six months after the second dose.
Professor Wei Shen Lim, chair of Covid-19 immunisation for the JCVI, said: “Whilst we don’t yet have data on protection against hospitalisation and unfortunately people dying from Covid-19, we can expect protection to be even higher than that figure of 93 per cent because that’s what happened so far in the vaccine programme.”
Shall I get my booster?
Yes - it may be the only shot at a normal Christmas.
You may be feeling confused about why you need to get yet another vaccine dose, if scientists said the first two worked so well.
There is a new Covid variant that has prompted a huge booster campaign.
Early indications are that this variant, called Omicron, may reduce the effectiveness of the vaccines, which were designed against the first Covid strain from Wuhan.
It means that in order to get the best protection against it, immunity levels need to be high.
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Speaking of the importance of boosters, Deborah Dunn-Walters, professor of Immunology, University of Surrey & Chair of the British Society for Immunology COVID-19 and Immunology taskforce, said: “Until the answers to these questions are known it is sensible to increase protective measures where we can.
“Since we know that immunity does wane to some extent, and that boosters can increase immunity, then accelerating the booster program will protect more people."
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