COVID-19: third and fourth doses for those with immunocompromise

Published 3 March 2022

The Immunisation Advisory Centre has clarified the requirements about COVID-19 vaccine doses (primary schedule and booster) for immunocompromised people over 18. 

COVID-19: third and fourth doses for those with immunocompromise

Three doses of COVID-19 vaccine, and a booster, is recommended for people who are older than 18 and immunocompromised. Ideally, the third dose is given between eight weeks and three months after the second dose. 

The fourth dose, which in this case is the booster, can be given any time after three months (ideally six months) after dose three. 

When the third dose is given more than three months after the second, it essentially becomes a booster dose (not part of a primary course). However, IMAC still supports a fourth dose being offered anytime from three months (ideally at six months) after the third dose.  

Operational note: Four doses in a series is off license so at least one of those needs to be scripted.  

If an immunocompromised patient:

  • gets a scripted third primary dose, then the fourth would be a booster
  • has a two-dose primary schedule and then a booster (which later is identified as a third primary dose) then their fourth dose would need to be scripted
  • In this case the third dose will be entered into CIR as their booster and the fourth dose will be recorded as an additional vaccine in the primary/standard case schedule. 

An interval of six months before the fourth dose is optimal but in the current environment the interval can be three months.