Why are you supposed to get a new flu shot every year?ANSWERThe flu vaccine confers lifelong immunity.The vaccine composition is not altered from year to year.The RNA genome of influenza mutates frequently, causing minor changes. This is referred to as antigenic drift.Influenza viruses may undergo a major genetic reassortment that dramatically changes HA and NA spikes, called antigenic shift.

Why do we need a new flu vaccine every year?Group of answer choicesThis is a myth, we only need to get the flu shot once in our lifetime.Getting the flu shot every year will prevent the disease from becoming endemic in the U.S.The virus changes rapidly so that the antibodies we grow for one variation will no longer be effective at killing the new variant of the virus.Only vulnerable populations (e.g., the elderly, immunocompromised individuals) need the flu shot every year

Explain why a new vaccine is made for Influenza each year?

What is the main reason for that every year another subtype of vaccine is recommended against seasonal flu?Because people travel a lot around the world.Because the main flu virus’s chemical composition is changing typically every year.Because we can only guess at the actual chemical composition of the main flu virus type.Because it increases the profit of pharmaceutical companies.None of the other answers is correct.

Vaccination typically involves at least two injections about 6 weeks apart. This drives which important process in adaptive immunity?Select one alternative:B cell replicationgene rearrangementT cell replicationaffinity maturation

Current seasonal influenza virus vaccines induce responses primarily against immunodominant but highly plastic epitopes in the globular head of the hemagglutinin (HA) glycoprotein. Because of viral antigenic drift at these sites, vaccines need to be updated and readministered annually. To increase the breadth of influenza vaccine–mediated protection, we developed an antigenically complex mixture of recombinant HAs designed to redirect immune responses to more conserved domains of the protein. Vaccine-induced antibodies were disproportionally redistributed to the more conserved stalk of the HA without hindering, and in some cases improving, antibody responses against the head domain. These improved responses led to increased protection against homologous and heterologous viral challenges in both mice and ferrets compared with conventional vaccine approaches. Thus, antigenically complex protein mixtures can at least partially overcome HA head domain antigenic immunodominance and may represent a step toward a more universal influenza vaccine.