With all those over 18 now able to book a Covid booster jab, many will find they are being given a different vaccine to their first two doses. But which combination is the most effective?
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With Christmas fast approaching, many Brits will be doing all they can to ensure the Omicron variant doesn’t ruin any plans they have with friends and family.
The new coronavirus variant is sweeping across the nation at an unprecedented rate, with 89,000 new cases being recorded on December 21.
One thing Brits can to do limit their chances of being infected is by getting the booster jab. The government set the ambitious target getting all eligible adults booster vaccines by the end of 2021.
All adults over the age of 18 are now able to get a booster, and they might find they are being offered a different one than their other two doses.
But does it matter if you get a different dose than you’ve previously had? And which combination is the most effective? Here is everything you need to know.
Does it matter if you mix jabs?
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It is perfectly safe to have a mix of jabs, with millions having done so already with scientists satisfied there is no risk, according to the Joint Committee on Vaccine Immunisation.
The committee said in September a “mix and match” approach is not a problem, adding: “mRNA vaccines provide a strong booster effect, regardless of whether the primary course was with the Pfizer-BioNTech (BNT162b2/ Comirnaty) or the AstraZeneca (ChAdOx1-S/Vaxzevria) vaccine.”
While the AstraZeneca jab was used heavily in the early days of the vaccine it is being less readily used in boosters and so many people are having to have a mix and match between the various jabs.
While it is not yet entirely clear how the jabs will fare as a sole response to Omicron, they remain the best option available at the moment.
Head of Immunisation at the UK Health Security Agency (UKHSA), Mary Ramsay, said: “These early estimates should be treated with caution but they indicate that a few months after the second jab, there is a greater risk of catching the Omicron variant compared to Delta strain.”
“The data suggests this risk is significantly reduced following a booster vaccine, so I urge everyone to take up their booster when eligible.”
All three of the major vaccines used in the UK – Pfizer, Moderna and AstraZeneca – all lower the risk of severe infection and hospitalisation, but vary in their ability to mute symptomatic infections. Read on for breakdown of the various levels of protection from different combinations.
Two doses of Pfizer
People with a double Pfizer dose from last year or earlier this year are thought to be 40% protected against Omicron.
However if you get a third jab of Pfizer this number is through to rocket to 75%, according to the UKHSA.
This trio of jabs is also thought to offer 94% protection against the Delta variant.
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This combination is currently thought to provide the strongest protection, although studies are ongoing as more data emerges.
Despite this, both Pfizer and Moderna are being offered and regarded as equals – they use the same mRNA technology and are thought to be similar in the protection they offer.
In a statement, the Joint Committee on Vaccination and Immunisation, said: “Both the Moderna (50 microgram) and Pfizer-BioNTech (30 microgram) vaccines have been shown to substantially increase antibody levels when offered as a booster dose and should be used with equal preference in the COVID-19 booster programme.”
Two doses of Moderna
This combo is thought to offer 86.7% protection against Delta, according to a study in the British Medical Journal.
However, its effectiveness against Omicron is not yet available at the time of writing as it awaits peer review.
However, laboratory testing is indicative that it will be effective against Omicron, with a 50mg dose thought to increase antibodies 37 fold.
The company are also developing an Omicron-specific vaccine.
Two doses of AstraZeneca
The jab stuck in the arms of most of Britain’s priority groups, it is feared it isn’t overly effective against Omicron.
It isn’t being offered as a booster with the two mRNA options being preferred.
However, if you have a dose of Pfizer after two AstraZenecas, you can still expect around 70% protection from Omicron symptoms, says the UKHSA. This is only 5% lower than the triple Pfizer cocktail.
This combination is also thought to be 93% effective against Delta based on data for over 50s.