Question

Jose and Karl were both exposed to the influenza virus at work. Jose had a flu shot made from killed influenza virus six weeks ago, but Karl has not gotten around to getting his vaccinations yet. Are they likely to get sick from this exposure to the virus, and what is likely to happen if they are exposed to it again? FOR THIS MY ANSWRER B @deepika.comet

Both Karl and Jose are likely to get sick this time since Jose's vaccine was dead, but neither will get it again once they acquire active immunity.

Karl will get sick and Jose will not this time, but neither will get this influenza aga

Answer 1

It's the second. It makes no sense to have a vaccine and have no benefit compared to those who did not get vaccinated. The virus in the vaccine has to be 'dead' or weakened so that it does not infect the subject with full blown influenza. However the immune system is able to recognise the killed influenza virus and make antibodies for it. Thus with subsequent exposure to the virus, with antibodies already generated and circulating in the bloodstream and thus active to target the virus, more antibodies can be quickly generated and T cells activated to execute a swift immune response.

Without the vaccine, the immune system is initially naive to the virus until there is already a substantial infection, after which the body will produce antibodies. So the immune response is much delayed.