Analysis of individual items suggests that this improvement is primarily driven by changes in four items: knowing that someone can be HIV-positive but not have AIDS (47% to 51%: OR = 1.29, 95% CI = 1.96–1.73), knowing that a high viral load means a weak immune system (32% to 42%: OR = 1.88, 95% CI = 1.39–2.53), knowing that a high CD4 count means a strong immune system (33% to 41%: OR = 1.62, 95% CI = 1.21–2.17), and knowing not to take extra ART following a missed dose (75% to 80%: OR = 1.51, 95% CI = 1.05–2.17). Here, CD4 is linked to AIDS.