What does antigenic drift cause?
The emergence of a new strain of influenza A due to antigenic drift can cause an influenza epidemic or pandemic. Antigenic drift is also known to occur in HIV (human immunodeficiency virus), which causes AIDS, and in certain rhinoviruses, which cause common colds in humans.
Can antigenic drift cause a pandemic?
Antigenic shift results in a new influenza A subtype that is so different from previous subtypes in humans that most people do not have immunity to the new virus. An antigenic shift can lead to a worldwide pandemic if the virus is efficiently transmitted from person to person.
What viruses have antigenic shifts?
Antigenic drift occurs in all types of influenza including influenza A, influenza B and influenza C. Antigenic shift, however, occurs only in influenza A because it infects more than just humans.
Do vaccines cause antigenic drift?
Because antigenic drift is a constant process that can occur after vaccines are manufactured, efficacy of influenza vaccines against antigenic drift variants is a desirable property.
What is antigenic shift influenza?
Another type of change is called “antigenic shift.” Shift is an abrupt, major change in a flu A virus, resulting in new HA and/or new HA and NA proteins in flu viruses that infect humans. Antigenic shift can result in a new flu A subtype.
Is antigenic shift unique to influenza?
Antigenic shift is a more major change in the influenza virus. This shift typically occurs when a human flu virus crosses with a flu virus that usually affects animals (such as birds or pigs). When the viruses mutate, they shift to create a new subtype that is different from any seen in humans before.
Why is hemagglutinin not a good target for influenza treatment?
Current flu vaccines induce antibodies that recognize the hemagglutinin head and inhibit its ability to mediate viral entry, but the hemagglutinin head mutates rapidly, resulting in vaccine-resistant influenza strains.