New vaccine on Influenza virus

•  A potentially ground breaking seasonal flu vaccine has been developed by a team from Oxford University. This could be significant to the world and to India.

About Influenza virus:

• Influenza or flu is a viral seasonal respiratory disease to which older people and young children are the most vulnerable.
• Influenza viruses are classified into A, B, C and D types — A and B are known to cause seasonal epidemics; C causes mild respiratory illness, but not an epidemic.
• Influenza D affects cattle. Influenza viruses annually affect about a billion people worldwide, and cause 250,000 to 500,000 deaths, mainly in the over-65 age group.
• This new vaccine will target influenza viruses A, B and C.

Analysis:

• Under a microscope, the flu virus looks like a spherical pin cushion with lots of pins sticking out of it. Available vaccines use surface proteins that lie on the outside of flu cells — the heads of the pins — to stimulate the immune system, which ultimately produce antibodies. But every year, as the virus changes, the surface proteins (hemagglutinin and neuraminidase) also change.
• Currently, every year, scientists are going back to the drawing board to predict how the virus might change, and what the new strain of flu might look like. Often, the vaccine doesn’t work well because “by the time the vaccine has been made, the strain of virus that is causing the illness has changed”.
• The new universal vaccine uses core proteins of the virus — lying inside the cushion — rather than the ones on the surface. This new vaccine targets conserved areas of the virus, and thus does not need to be changed year to year.
• The new vaccine will stimulate the immune system to boost influenza-specific T-cells (the body’s own immunity-building cells), instead of antibodies, that kill the virus as it tries to spread through the body.
• Everyone has some influenza-specific T cells already, but their numbers are often too low to be protective. T-cells can help fight more than one type of flu virus and this, according to the researchers, means more people could be protected and the severity and duration of flu may be reduced.
• Current vaccines are only effective in 30% to 40% of over-65s as the immune system weakens with age.
• The flu burden in India is huge; the total number of cases until October 1 this year had crossed 36,000 countrywide, and the number of deaths was close to 2,000.

By: Vishal