What is the primary characteristic of the HBV virus?

The primary characteristic of the HBV virus, or hepatitis B virus, is that it is indeed significantly more contagious than HIV. Hepatitis B is transmitted through contact with infectious body fluids, which include blood, semen, and vaginal secretions. The level of infectivity is a critical aspect of the virus; it can survive outside the body for extended periods and still remain infectious, making it much easier to spread compared to HIV. This characteristic underscores the importance of preventive measures such as vaccination, especially for high-risk populations.

The other options misrepresent critical aspects of HBV. For example, while the virus can enter the body through more than just sexual contact, suggesting that it is only transmitted this way limits understanding of its transmission routes, which include sharing needles and mother-to-child transmission during childbirth. Additionally, unlike bacterial infections that can be treated with antibiotics, viral infections like HBV often require different approaches, such as antiviral medications, and may not always be curable. The notion that it primarily affects the lungs is also misleading, as HBV primarily targets the liver, leading to severe complications such as cirrhosis and liver cancer.