Having collaborated with Abraham Karpas on some articles on passive immune therapy ("Medics see red over bad blood", THES , July 6), I can confirm that statistical evidence favours the therapy's effectiveness.
There were statistically significant improvements in the survival of patients with Aids in the French trial mentioned in the article and there are encouraging data for those who have not yet progressed to clinical symptoms. I can supply detailed statistics.
There is also the possibility that treatment of pregnant HIV-positive women with passive immune therapy could reduce the risk of infection in the child. Certain drugs can do this, but there is a risk of adverse effects.