Surveillance has shown that there has been no significant evidence of antigenic drift
among circulating A(H3N2) viruses since the selection of viruses for the 2018-19 Northern Hemisphere vaccines was made in February.
Analysis of antigenic drift
in recently isolated influenza A (H1N1) viruses using monoclonal antibody preparations.
In the 2014-2015 influenza season, an antigenic drift
in the circulating H3N2 virus rendered influenza vaccines only 23% effective in preventing laboratory-confirmed influenza.
The ZELS and BBSRC funded amount of 32.67 millions for the project title "Combating Avian Influenza Through systematic Analysis of Antigenic Drift
Genetic Variations development Of Novel Diagnostic Tool and Vaccines".
Accumulation of genetic mutations termed antigenic drift
, allows influenza viruses to inflict yearly epidemics that may result in 250,000 to 500,000 deaths annually.
Due to viral genetic changes (antigenic drift
), vaccines largely protect against homologous strains only.
"Finally, significant antigenic diversity of noroviruses and the constant antigenic drift
These seasonal epidemics are the result of antigenic drift
, a phenomenon caused by mutations in two key viral genes due to an error-prone RNA polymerase.
This evasion strategy, called antigenic drift
, is why a new flu vaccine is necessary every year, a process that can take upwards of seven months.
The Influenza A Virus (IAV) undergoes major and minor genetic variations, the yearly antigenic drift
resulting in as minor as a single amino acid mismatch.
Current influenza vaccines may be safe and immunogenic, but they are highly vulnerable to antigenic drift
and shift, which compromise efficacy and require reformulation and repeated immunization.
During the 2009/2010 Northern Hemisphere influenza season, little antigenic drift
occurred in circulating H1N1 (7) and the clinical manifestations remain generally mild.