Which one of the following statements is not correct?

The correct option/answer is: Hepatitis B. unlike Hepatitis C, does not have a vaccine.

Let us analyze each statement step-by-step to understand why this statement is incorrect (and thus the correct choice for this question):

1. Hepatitis B virus is transmitted much like HIV:
This statement is correct. Both Hepatitis B virus (HBV) and Human Immunodeficiency Virus (HIV) are transmitted through contact with infected blood, semen, and other body fluids. Common modes of transmission include sexual contact, sharing needles/syringes, or transmission from an infected mother to child during childbirth.

2. Hepatitis B, unlike Hepatitis C, does not have a vaccine:
This statement is INCORRECT (false). In reality, there is a safe and effective vaccine available to prevent Hepatitis B infection. Conversely, there is currently no vaccine available for Hepatitis C. Therefore, claiming that Hepatitis B lacks a vaccine while Hepatitis C has one is factually untrue, making this statement the correct choice to pick.

3. Globally, the number of people infected with Hepatitis B and C viruses are several times more than those infected with HIV:
This statement is correct. According to the World Health Organization (WHO), chronic viral hepatitis (HBV and HCV combined) affects hundreds of millions of people worldwide, significantly outnumbering the total population living with HIV.

4. Some of those infected with Hepatitis B and C viruses do not show the symptoms for many years:
This statement is correct. Both Hepatitis B and Hepatitis C infections can remain asymptomatic or silent for decades while silently causing progressive liver damage, such as cirrhosis or liver cancer.

Hence, the incorrect statement among the options is: Hepatitis B. unlike Hepatitis C, does not have a vaccine.