I had a single dose of the hepatitis A vaccine 10 years ago. Is it still valid?

In 2013, on a trip to Asia, I got a dose of the hepatitis A vaccine. However, I never got the expected second dose. Do I have to start the cycle again to be covered?

No, you absolutely must not repeat the cycle, it is sufficient to complete with the second scheduled dose. In fact, we know from published studies that a single dose of inactivated hepatitis A vaccine – a very effective vaccine – protects for about ten years.