The medics had already been sentenced to death twice by a Libyan court - in May 2004 and then again in December 2006, following an appeal and lengthy re-trial.
The prosecution blamed the nurses and Alhajouj for starting an HIV epidemic in a hospital in the eastern town of Benghazi in the late 1990s.
The convictions were based mainly on confessions from some of the nurses, who say they are innocent and were tortured to admit guilt.
At least 53 of the infected children have already died of AIDS but the defendants supporters say the epidemic had broken out because of poor hygiene long before the arrival of the defendants.
Bulgaria, the EU and the US have called the verdicts unfair and have stepped up diplomatic pressure on Tripoli to release the six.
Even if the conviction in the HIV case is upheld, a government-led Libyan body called the high judicial council can overturn it.
But experts say that is likely to happen only if Western nations and Libya can agree on how much should be paid towards a fund that has been set up to help the hundreds of HIV-infected Libyan children.
Prospects of such a deal, long discussed by Libya and Western officials as a face-saving solution, have receded amid a recent war of words between Libya and Bulgaria over the case.