This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
Which positive test does not necessarily indicate HIV infection in a newborn ? 
Select and explain. 
A. ELISA for HIV IgG antibody, B. p24 antigen, C. Virus culture, D. ELISA for HIV IgA antibody
A: ELISA for HIV IgG antibody
Answer: A: ELISA for HIV IgG antibody 
Explanation: None