Is Hepatitis B always Contagiuos ?

One of my family member got detected with Hepatitis-B.  I cannot access the reports but heard he's only a carrier. He has been suffering from mild jaundice,stomach pain and loss of appetite. He has frequent stomach problems too.

Would that mean he'll always be contagious to other member of the family since none of us are vaccinated against

Hepatitis-B ? Also is there any form of Hepatitis-B that is not contagious ?  

I'm a 33-year old adult. Would it help to get vaccinated now if I'm not already infected ?  Also my son 2 and half year

old, if he is vaccinated , is there any possibility for him to get infected ? Is the vaccine 100% successfull ? Thanks a lot.

[cajim]

The same Hep B patient may be in a period of greater or less infection depending on his lab readings.

People around the patient are very safe if they are HBsAB positive, not whether or not they have been vaccinated.

[Faridabad]

Thank you for your quick response. One more clarification please. Is it possible to have Hep B and not be contagious to others ( not HBsAB positive ) ?  I'm asking because he's saying, he is only a carrier and cannot cause it to others.

[cajim]

If you are HBsAB positive, then you can't get HBV from him regardless what level he is; if you are HBsAB negative, the risk is not zero even if he is a healthy carrier.