On average how long does the body hold immunity to a particular strain of the norovirus? is it possible to catch the same strain twice w/in a few mos?

Norovirus infection: Norovirus is now the most common cause of viral gastroenteritis. A functioning immune system should resolve the infection within 2 weeks and protect you against the same serotype of norovirus, But other causes of diarrhea, or other serotypes of norovirus may be responsible for your symptoms. There are now stool tests to detect this that are very sensitive.