Yes. Different strains of the influenza virus pop up every year. The flu vaccine is designed to protect people from the particular strain of flu that will be prevalent each flu season. For this reason, it is a good idea to get the flu vaccine every year.
Yes. Having a case of influenza does not protect you from other strains of the virus that circulate each year. Current influenza vaccines protect you against what are predicted to be the most common strains circulating that year so get your flu shot now.
Yes.. Depending on your medical history, vaccination for both infections is recommended.
H1N1 vaccine (swine) The most recent (last 2 yrs) have had the h1n1 strain as part of the regular flu shot in the us. There would be no benefit in seeking out older single strain h1n1.