Immunological conditions indicating that a change to second-line therapy is warranted include:
Persistent decline in CD4 percent over 2 months in absence of TB
Rapid and substantial decrease in absolute CD4 count (i.e. > 30% decline in < 6 months)
Return of CD4 percent to or below pre-therapy baseline
Note: CD4 percent should not be measured during an intercurrent infection; preferably it should be determined 1 month (or more) post-resolution.
If there is a modest decline in CD4 percent (< 5%) and if there is no failure to thrive, do not change medication, but maintain close monitoring.
Despite a good clinical and immunological response, viral resistance will occur in the absence of complete viral suppression. Many experts will delay changing therapy unless there are signs of clinical or immunological progression.