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Statement: National AIDS Trust, BHIVA, and THT community guidance on COVID third doses & boosters

Friday, September 24, 2021

Recommendations from the Joint Committee on Vaccination and Immunisation (JCVI) on COVID vaccine third doses and boosters: update 24 September 2021

Guidance for People Living with HIV from the British HIV Association (BHIVA), National AIDS Trust and the Terrence Higgins Trust (THT)

Updated advice on COVID vaccines

The Joint Committee on Vaccination and Immunisation (JCVI) has updated its advice on COVID vaccination:

  • A third dose should be offered to those with severe immunosuppression (a weaker immune system) from eight weeks after their second vaccination
  • A booster vaccine should be offered to those who are more likely to be at risk from serious disease (priority groups 1 to 9 in the first phase of the vaccine programme) approximately six months after their second vaccination.

What’s the difference between a third dose and a booster?

Third dose

This third dose is for people who have a weaker immune system so two doses may not be enough. There is some evidence that a third dose will improve vaccine response. The third dose is part of the “primary,” or first, course of vaccinations and should be given at least 8 weeks after the second dose.

People whose immune system is weaker because of medical conditions or treatments, who therefore need a third dose, are listed in Reference 1.  This guidance applies to all people age 12 or older. The third dose is being offered to people now - they will be contacted by their GP or HIV clinic.


Everybody’s response to vaccines gets weaker over time, even people with healthy immune systems. The effectiveness of the COVID vaccine is expected to drop after 6-8 months, which is why some people are being offered boosters now. At the moment boosters are only being offered to people who were in priority groups 1-9 in the first phase of COVID-19 vaccinations. This includes people at greater risk of COVID-19 because of particular health conditions, including all people living with HIV.

These health conditions include everyone living with HIV, so everyone living with HIV should have a booster from 6 months after the second vaccination. 

Only some people with HIV will be offered a third dose. People with HIV who are not offered a third dose will be offered a booster.  We don’t yet know if people who need a third dose will also need a booster in 6 months time.  As long as you and your HIV clinic keep track of what you have had, and decide whether you need a third dose, then you will get the vaccines you need.

This can be quite confusing, but the most important thing is that you get another vaccine dose.

Do all people with HIV need a third dose of COVID vaccine now?

No.  Evidence to date shows that people with HIV who are undetectable respond as well to vaccination as people who do not have HIV. Most people in studies had high CD4 counts (above 350).  There is some evidence that shows people with a low CD4 count respond less strongly to vaccination, which is why they may be offered a third dose now.

The JCVI recommends everyone living with HIV aged 12 years or older with a CD4 count less than 200 should have a third dose 8 weeks after their second vaccination or as soon as possible after that. BHIVA supports this recommendation and also advises a third dose for the following people:

1) People who had a serious HIV-related illness in the 12 months before their first COVID vaccine dose (e.g. AIDS-defining illness, tuberculosis).

2) People not taking recommended HIV treatment.

3) Some people who have a detectable viral load despite treatment. Their clinic will consider other things like CD4 count and then talk to them on a one-to-one basis about whether an immediate third dose is needed.

Some people with HIV have been offered a third dose even if they do not need one.  This may be because GPs do not have up to date information on everyone’s CD4 count or because they are erring on the side of caution. This is fine, as people with HIV will need a booster anyway, although it may mean they get a booster earlier than recommended, which is also fine as long as it is 8 weeks after the second vaccine dose.

How will I find out if I need a third dose?

HIV clinics have been asked to identify and contact people who need a third dose, and then to liaise with the patient’s GP, unless you have asked your clinic not to share your status with your GP. If your HIV clinic has contacted you about a third dose, but you do not hear from your GP directly, for example by letter or text message, please contact the practice to arrange a vaccine.

If your clinic has contacted you about a third dose, and you are not registered with a GP, or if your GP does not know about your HIV status, they will refer you to a vaccine centre in your area.

All people with HIV should be contacted by their GP or the Department of Health about getting a booster – if you do not hear anything, speak to your GP. If your GP is not aware of your HIV status, speak to your HIV clinic.

What is the recommended gap between doses?

The third dose should be given at least 8 weeks after the second dose. If you have a low CD4 count, and have just started HIV treatment, your clinic may advise you to wait a few weeks for your third dose.

A booster should be given at least 6 months after the second dose.

What type of vaccine will the third dose be?

For third doses, JCVI recommends an mRNA vaccine, such as Pfizer or Moderna. In some situations the third dose can be with an Astra Zeneca vaccine.

For boosters, JCVI recommends a Pfizer vaccine as first choice, followed by Moderna. In some situations Astra Zeneca can be used.

Immunity testing

Blood tests have been used in research trials to measure how strongly someone has responded to the COVID vaccine. However, it is not currently recommended that blood tests are done to decide if a third vaccine is needed.



For further information, please contact or for media enquiries, please contact Jo Josh at or +44 (0)7306 391875.

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