What the difference is between third primary dose and a booster?
This is causing a lot of confusion!
A ‘booster dose’ is now being offered to all people age over 50 who are more than 6 months (or 180 days) after their 2nd dose of COVID-19 vaccine. The idea is to boost the immune response in all people aged over 50 to protect them from waning antibody levels. There is strong trial data to support this extra booster, and many countries have already adopted this approach with good effect.
A ‘third dose / 3rd primary’ is an extra dose given to some patients who are at a higher risk of not having responded well to their first 2 doses as part of their initial course of vaccination. Although 2 doses is usually enough for most patients, if you suffer from a dampened immune response (due to disease or some medication) then data suggests that you might not create an adequate protective (antibody) response to the standard 2 vaccine approach. For this reason a limited number of patients are recommended to have a third dose around 8 weeks after their second dose to ensure a safe and effective response. This is separate to any booster dose.
Who is eligible for a standard COVID-19 Booster?
The programme is being rolled out to the same priority groups as previously. This means care home residents, health and social care workers, people aged over 50, those aged 16 to 49 years with underlying health conditions that put them at higher risk of severe COVID-19, adult carers, and adult household contacts of immunosuppressed individuals will be prioritised.
The booster vaccine will be offered at least six months (180 days) after a second vaccination and the NHS should contact people directly to let them know when it is their turn to get their booster vaccine.
Why are some patients being offered a third primary does at 8 weeks after their 2nd dose?
Preliminary data from studies have shown that many patients with an immune problem or underlying health conditions, do not make an antibody response at all to vaccination or make a response that this is much lower than for someone with no underlying disorders. There will also be other benefits to the immune system including T cells but again the responses to these are still under investigation. Having no or low anti-bodies does not mean that you do not have any protection from serious covid infection, but it may mean that you could be at higher risk than someone who had a strong anti-body response.
What are the timings of the third primary dose?
A third dose is recommended for some high risk patients at least 8 weeks after the second dose of the vaccine. Speak to your specialist team about when you should get your third dose of the vaccine, as they will be able to time this around your treatment in order to give you the highest possible level of protection from COVID-19.
Who should get a third primary dose at 8 weeks after their 2nd dose?
In September 2021, the JCVI announced that people who have severely suppressed immune systems at the time of their first and second doses of the vaccine would be able to get a third dose. As stated above this is NOT a booster dose, but an additional ‘top-up’ dose to increase protection from COVID-19 for people who may not have not had a good response from the first two doses.
Which medication taken in the 3 months before a 2nd vaccine mean that a third primary dose is required?
Based on the guidance put out by the JCVI, Crohns and Colitis UK has summarised the info clearly here. All people taking the following treatments in the 3 months before your 2nd vaccine should be offered a third dose of the vaccine:
- Conventional DMARDs, such as methotrexate (more than 20mg / week), azathioprine (more than 3mg per kg per day), mycophenolate mofetil.
- Anti-TNF biologics, such as infliximab, adalimumab, etanercept, golimumab, certolizumab pegol.
- Other biologics, such as tocilizumab, abatacept, ustekinumab, secukinumab, belimumab.
- JAK inhibitors, such as baricitinib, tofacitinib, upadacitinib, filgotinib.
- Prednisolone (steroid tablets) at doses above 10mg per day, (or 20mg or more prednisolone per day for more than 10 days).
If in doubt, please check with your specialist team or GP.
Which vaccine will be used for third primary doses (and COVID-19 boosters)?
The JCVI are recommending that one of the mRNA vaccines (Pfizer or Mederna) should be used for all boosters and third primary doses. This will be the case irrelevant of which vaccine you had before.
People will be offered either a full dose of the Pfizer/BioNTech vaccine or a half dose of the Moderna vaccine, following scientific evidence showing that both provide a strong booster response. This will be regardless of which vaccine the individual previously had.
Where neither can be offered, for example for those who have an allergy to either vaccine, the JCVI advise that the Oxford/AstraZeneca vaccine can be used for those who received this vaccine for their first and second doses.
Is it OK to mix vaccines?
Because the JCVI are recommending the mRNA vaccines for third primary doses and boosters, this means that people who previously received the AstraZeneca vaccine are now likely to receive the Pfizer or Moderna vaccine as their third dose.
Studies suggest that mixed vaccines may give a better immune response, and offer improved protection. So having the AstraZeneca vaccine followed by the Pfizer vaccine probably gives a better immune response than two AstraZeneca vaccines, although studies did not include people who were immunosuppressed.
If I get a third primary dose will I also need a booster (4th dose)?
Yes. Booster jabs are already being offered to people aged over 50 who are likely to have made a good response to their first 2 vaccines but who would be at increased risk of COVID-19 infection if their immune response wanes with time. This booster should be at least 6 months (180 days) after getting the first 2 doses to maintain good levels of protection.
The JCVI are anticipating that those that require 3 doses for their primary course will still need a ‘booster’ or 4th dose, 6 months later.
Who will contact me about my 3rd vaccine dose?
Good question! And there is currently no fixed process for this – so please ensure if you have any doubts if you need a third primary dose that you contact your specialist team or GP, to ensure that you are not missed, and that you get protected.
You might be called from a variety of places:
- You will probably be recalled by the same place you had your first 2 doses (primary course)
- You may be recalled by your own GP
- You may receive a letter from the NHS inviting you to book
If you received a letter about being vulnerable or extremely vulnerable in the past, or were invited to be vaccinated ahead of your age group, you should be on a central list and should be contacted. However, the lists may not be fully accurate or up to date, and sometimes the way that your condition is put into GP databases may not trigger the central list – so it is possible that you could be missed.
If in doubt please speak to your specialty team or your nurse specialist who should be able to assist.
Where will I be able to get my third primary dose or COVID-19 Booster?
Plans for the rollout will use the existing networks in place for the COVID-19 vaccination programme, including:
- Local vaccination services co-ordinated by GP groups (primary care networks)
- Community pharmacies
- Some limited hospital centres
- Mass vaccination centres across the country, ensuring people can access a booster dose regardless of where they live.
The NHS should contact people directly to let them know when it is their turn to get their booster vaccine and outline options available.
When should I hear about my third primary dose?
The announcement and roll out of the boosters has been very rapid and it will be a challenge to get all eligible half a million individuals vaccinated by the target date of 11th of October. Hopefully they will be done as soon as possible.
What other measures should I take?
Vaccines have been very effective, but regardless of vaccine status it is still worth continuing with cautions including wearing masks, avoiding crowded areas as far as possible (particularly indoors or poorly ventilated) and trying to avoid close contact with others especially if they are known to be unwell.
What should I do if I have not heard about my third primary dose?
Please contact your hospital specialist and they should be able to support or confirm your eligibility. Your hospital specialist does not have access to give you a COVID-19 vaccines as these are all being delivered through vaccine centres. The only exception to this is if you are involved in a research study.
Alternatively, contact your GP surgery to ask for advice and to see whether they have started contacting their patients eligible for a 3rd dose, or try the central covid vaccination helpline number on 119 free of charge to ask for advice.
Are the COVID-19 vaccines safe for me?
The currently available COVID19 vaccines are safe for people with immune problems (including the Pfizer/BioNTech, Moderna and Oxford AstraZeneca vaccines). Studies have been done that show a 3rd dose is safe and effective at enhancing the immune response to vaccination. This is true regardless of which 2 vaccines you had first.
It is likely that you will have some pain at the site of the injection and you may have other side effects including feeling tired, achy, feverish or have a headache. If you do have side effects, they usually occur shortly after the vaccination and usually resolve within one to two days. If you have a more severe adverse reaction it is important to tell your GP or consultant so they can help you and also report it to the Yellow Card Scheme.
Will people know if they have got a better immune response after the third?
There is no routine antibody testing in the NHS to assess the response to vaccination. There are studies which are exploring this in patients with immune problems. These give some individuals their results back but importantly scientists are trying to understand what these results mean for the whole immunodeficiency population. There is not YET enough available to know what level of antibody gives a protective level, or how long this protective level might last in healthy individuals or those with an immune problem.
Can I have my flu jab at the same time as my 3rd COVID-19 vaccine dose?
Yes, the Flu and the COVID-19 vaccines can be given at the same time. However this will be a personal decision.
The JCVI advised that the flu and COVID-19 vaccines can be co-administered (given at the same time). It is important that people take up the offer of both vaccines when they receive it, so people are encouraged to get both vaccinations as soon as possible rather than waiting for the possibility of getting them together.
A UK study, called the ComFluCOV, has found that this is a safe and effective strategy. Also from a practical point of view it is often easier to arrange both Covid and Flu vaccines at the same time as a single appointment. This is especially important if a patient would struggle to return for the other vaccine at another time for practical reasons.
This is correct as of 4.10.2021
Prof Alex Richter Prof of Immunology
Dr Simon Hodes General Practitioner