This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology (General Propeies, DNA Viruses), Subject name: Microbiology
Which of the following is true regarding HPV vaccine strains? Current WHO recommendations for HPV vaccination is: 
Select and explain. 
A. Bivalent vaccine 6,11 strains, B. Quadrivalent vaccine 6,11,16,58 strains, C. single dose to girls if initiated prior to 15 years of age, D. 2 doses recommended irrespective of age, gender, type of vaccine
D: 2 doses recommended irrespective of age, gender, type of vaccine
Answer: D: 2 doses recommended irrespective of age, gender, type of vaccine 
Explanation: 2 doses of HPV vaccine are recommended irrespective of age, gender, type of vaccine. Option 1: Bivalent vaccine- serotype 16,18 (cervarix). Option 2: Quadrivalent vaccine- serotype 6,11,16,18 (Gardasil,Merck). Option 3, 4: The first dose is recommended for most persons before 15 years of age and the second dose should be given 6 to 12 months after the first dose. A 3-dose schedule is recommended for people who get the first dose on or after 15 years of age, and for people with ceain immunocompromising conditions.