Explain why a person infected with HIV may eventually die from a disease caused by a different pathogen.

OCR GCSE Biology A: Gateway Science (J247) — B6.3 Monitoring and maintaining health · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

HIV is a communicable disease that progressively damages the body's ability to fight infection. The later stage of HIV infection is known as AIDS.

Model answer (4 marks)

HIV attacks and weakens the immune system over time.
This leads to AIDS, where the immune system can no longer respond effectively to pathogens.
The person becomes vulnerable to infections that a healthy immune system would normally overcome – opportunistic infections.
Death therefore results from a secondary or opportunistic infection rather than from HIV itself.

Examiner tips

Use the word ‘opportunistic infection’ to show understanding of the term.
Explain the sequence: HIV → immune weakness → AIDS → vulnerability → secondary infection → death.
Keep the answer concise and use the exact terminology from the mark scheme.

Common mistakes

Confusing HIV with AIDS – not explaining the progression.
Failing to mention opportunistic infections as the cause of death.
Using vague phrases like ‘other diseases’ instead of ‘secondary or opportunistic infections’.

Mark scheme (4 marks)

HIV attacks / weakens the immune system over time
This leads to AIDS, in which the immune system is no longer able to respond effectively to pathogens
The person becomes vulnerable to infections that a healthy immune system would normally overcome (opportunistic infections)
Death therefore results from a secondary / opportunistic infection rather than from HIV itself

Key terms in this question

HIV · pathogen