Naked Science Forum

Life Sciences => Cells, Microbes & Viruses => Topic started by: tkadm30 on 30/12/2015 13:22:53

Title: What is a vaccine escape and low reactor vaccine isolate?
Post by: tkadm30 on 30/12/2015 13:22:53
Is the qualification for being a 'low reactor' vaccine isolate requires a vaccine escape/mismatch?

How do a vaccine mismatch may result in a antigenic shift/drift?

Is the recombinant H1N1 vaccine engineered to mutate from accidental vaccine escapes, leading to genomic RNA polymorphism ? (RNA splicing)



Title: Re: What is a vaccine escape and low reactor vaccine isolate?
Post by: chris on 30/12/2015 14:26:53
Vaccine escape is where the circulating strain of an infectious disease mutates (drifts) such that the immune response elicited by vaccination is ineffective.

Influenza achieves this by having a relatively high mutation rate. This is a consequence of errors introduced into the genome by the RNA polymerase that replicates the viral genetic material during infection. Owing to a lack of proof-reading (because RNA is single-stranded and so there is no backup copy against which to compare and check the integrity of the genetic message) mutations creep in at the rate of about 1 in every 10,000 genetic letters (bases) replicated. This equates to about on mutation per viral genome, on average.

Owing to this steady drift phenomenon, as the virus circulates each year strains are selected that replicate well and transmit readily; inevitably, this often means strains are disclosed that are vaccine-resistant. In effect, through the use of the vaccine we are forcing the evolution of the flu virus to take a specific path.
Title: Re: What is a vaccine escape and low reactor vaccine isolate?
Post by: tkadm30 on 26/01/2016 11:57:56
Thanks chris for the info.

Can a vaccine escape (virus) recombine itself with human polyclonal antibodies from a different Influenza strain ? Note that the vaccine escape isolate (low reactor) has a genetically-modified RNA polymerase to facilitate Influenza reproduction between humans.