2023TrialShort answer

Q33 (b)

4 marks

Question

Human papillomavirus (HPV) is a group of viruses that infect the skin and mucous membranes of humans. HPV viruses are classified into different serotypes based on the DNA sequences of their viral genomes. Each HPV type is identified by a specific number (e.g., HPV-16, HPV-18, etc.). HPV types can cause changes in the cells of the cervix, leading to the development of precancerous lesions. If these lesions are left untreated, they may progress to invasive cervical cancer. HPV binds to the surface of epithelial cells and gain entry via endocytosis. Once inside the cell it introduces its viral DNA into the cells nucleus. It uses the hosts cell’s machinery to produce a viral E6 protein. Schematic of HPV infection of a epithelial cell Adapted from Human Papillomavirus and Oropharynx Cancer: Biology, Detection and Clinical Implications

The graph below shows the ten year cumulative incidence rate of cervical precancer by different HPV serotypes. Patiens were tested for HPV at the beginning of the 10 year period.

Analyse the trends shown in the data.

Luna-requested uncropped source page for question 33.b; requires human review and cropping — Reviewed visual · source page 28

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Solution

Criteria	Marks
Uses data to describe trends for all four groups, compares incidence by serotype, and draws implications.	4
Uses data to describe overall trends for two groups and draws implications.	3
Correctly describes trends for two groups, or briefly outlines all four.	2
Briefly outlines a trend or identifies an implication.	1

Sample answer:

HPV 16 and HPV 18 have a higher risk of developing cervical precancer when compared to all other HPV types and definitely in comparison to women who are HPV negative.

HPV 16+ showed the largest increase in cumulative incidence % in the first 15 months, increasing from 0 to ~11%. HPV18+ showed a significant increase between 15 and 39 months increasing from 0 to 10%. HPV 16+ continued to increase to 20% from 39 months. HPV 18+ cumulative incidence remained constant from 39 to 75 months. After this it increased 15%.

Other strains of HPV had a significantly lower incidence rate of ~1% from 27 months onwards.

If patients tested negative to HPV the incidence rate throughout the study was less than zero.

Supplied marking guidance · human reviewed

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Syllabus alignment

Module 7 · Infectious Disease

Prevention, Treatment and ControlInterpret infectious-disease incidence and prevalence data in populations.

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