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Explainer | Coronavirus: why a third vaccine shot is important for people who are immunocompromised
- Some people with immunodeficiencies generate a lower immune response to Covid-19 vaccines, leading to increased breakthrough infections among them
- While a third dose for all ages could generate optimal immunity, the WHO is calling for poorer countries to have access to vaccines first
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A number of countries including the United States and the United Kingdom are moving to make a third dose of a Covid-19 vaccine available to people who are immunocompromised.
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But why are people with weaker immune systems at the front of the queue for a third dose?
As the global Covid-19 vaccine roll-out continues, emerging data is showing those who are immunocompromised are not necessarily as well protected by the first two doses. So for these people, a third dose, sooner rather than later, could be particularly beneficial.
Who is ‘immunocompromised’?
People who are immunocompromised have conditions called immunodeficiencies, where part of their immune system is missing or not functioning as well as it should.
Around 2.8 per cent of adults in the US are immunocompromised, and the rate is expected to be similar in Australia and other countries.
Immunodeficiencies are broadly divided into two categories:
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– primary immunodeficiencies are very rare, often inherited conditions caused by mutations in our DNA
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