Flu Pandemics - Are we due for another one?

Eighty years after the flu pandemic of 1918, the threat of another pandemic is still real.

October 22 marked the anniversary of the flu pandemic of 1918 which spread globally in little over a year and killed at least 50 million people.  Commonly referred to as Spanish flu, the illness caused more deaths than World War I or the four years of Bubonic plague outbreak in the Middle Ages.  Now, almost 80 years later, medicine has advanced significantly, yet the threat of pandemic flu is still very real.  Last year, fear of a bird flu epidemic dominated news headlines as a number of humans in different regions were infected with the virus after being in close proximity to infected birds.  If the virus were to mutate and become transmittable from person to person, a flu pandemic could emerge with effects just as catastrophic as the mass flu outbreak of 1918. 

New strains of flu are the most likely to cause epidemics, but how do they come about? When the proteins (or antigens) on the surface of a flu virus change frequently, different strains of flu are created with new variations of surface proteins. Although differences between strains are usually relatively minor, occasionally major changes to the proteins will occur which can result in a virulent strain that causes pandemic flu.  The population will have little or no immunity to such a new strain and this makes the virus more likely to spread quickly from person to person.   With common flu, for example, a new flu vaccine is required each year since immunity to one strain will not necessarily provide immunity to other similar strains.

New vaccines

Developing a vaccine for a new strain can take time.  Dr. Jim Robertson, principal scientist at the National Institute for Biological Standards and Control (NIBSC) in the UK, predicts that today, the complex genetic task of developing a suitable vaccine would take 1-2 months alone and producing it, a further 4-5 months.  The reality is therefore that a pandemic flu could progress unopposed for up to six months.  Furthermore, in a pandemic situation it is likely that two doses of vaccine would be required for it to be effective. Experts claim that it is inevitable that vaccines would be limited during the first year of an outbreak, which would cause the ethical dilemma of deciding who should be administered the vaccine first.