People with weakened immune systems (immunocompromise)
People with immunocompromise includes those who have a medical condition or are taking medications that weaken their immune system. People with immunocompromise, including those living with HIV, have a higher risk of severe illness from COVID-19, including a higher risk of severe illness and death. The Australian Government strongly recommends people with immunocompromise receive a COVID-19 vaccine. COVID-19 vaccination decision guide for people with immunocompromised.
· ATAGI recommends a 3rd primary dose of COVID-19 vaccine in severely immunocompromised populations to address the risk of suboptimal or non-response to the standard 2 dose schedule.
o The 3rd dose is intended to maximise the level of immune response to as close as possible to the general population.
o For people who have had a single dose for their primary course (e.g. COVID-19 Vaccine Janssen), this advice would apply to a 2nd primary dose.
· ATAGI recommends that all individuals aged ≥12 years with certain conditions or on therapies leading to severe immunocompromise, receive a 3rd primary dose of a COVID-19 vaccine.
· An mRNA vaccine (Pfizer or Moderna) is preferred to Vaxzevria (AstraZeneca) for this 3rd dose. AstraZeneca can be used for the 3rd dose for individuals who have received AstraZeneca for their first 2 doses if there are no contraindications or precautions for use, or if a significant adverse reaction has occurred after a previous mRNA vaccine dose which contraindicates further doses of mRNA vaccine (e.g. anaphylaxis, myocarditis).
· The recommended interval for the 3rd dose is 2 to 6 months after the 2nd dose of vaccine.
o A minimum interval of 4 weeks may be considered in exceptional circumstances
(e.g. anticipated intensification of immunosuppression; outbreaks).
o People who have received a 2nd dose more than 6 months ago should receive a 3rd dose as soon as feasible.
· An individual with an unlisted condition should only be considered for a 3rd dose where the treating physician has assessed the patient as having a similar level of severe immunocompromise to the listed conditions, and where the benefits of a 3rd dose of COVID-19 vaccine outweigh the risks.
· Individuals who currently are not severely immunocompromised but who will commence significant immunosuppressive therapy ≥2 weeks after their 2nd dose do not require a 3rd dose, as it can be expected that an adequate response to 2 primary doses will be achieved.
· People with functional or anatomical asplenia do not require a 3rd primary dose.
· Antibody testing is not recommended to assess for immunity to SARS-CoV-2 following
COVID-19 vaccination, including in immunocompromised individuals after a 2nd or 3rd dose. There are no serological assays that provide a definitive correlate of immunity to SARS-CoV-2.
· In severely immunocompromised individuals, ATAGI does not recommend more than three doses currently. Some severely immunocompromised individuals who fail to respond to 3rd doses may not respond to further doses.
· Protection from 3 primary doses in severely immunocompromised individuals may still be lower than the general population. Risk mitigation strategies such as mask wearing and social distancing should continue to be used even after receipt of a 3rd dose.