Table of Contents
Seasonal flu is treated by many people more like annoyance rather than something serious. Although it is frequent (many people experience it as often as every year) it rarely leads to significant problems among generally healthy individuals. It can, however, be a big threat for those with weaker health: young children, elderly people and people suffering from chronic serious illnesses.
Even mild forms of flu tend to produce an array of unpleasant symptoms and affect people’s normal life and work.
Influenza virus mutates quickly causing emergence of new infectious strains of flu
On some rare occasions, seasonal flue comes in dangerous forms and becomes a global pandemic.
Estimates suggest that it killed 50 to 100 million people – 3 to 5% of world population at the time.
It is interesting that most forms of seasonal flue that occurs almost every year are related to the Spanish flu strain. They belong to the same H1N1 family. Recent pandemic of swine flu was also caused by virus of this subtype.
Why flu vaccines offer little protection?
The problem of preventing flue lies in the fact that each seasonal variety is associated with a different strain of virus. Influenza virus mutates very quickly, but vaccines provided at the start of each flu season actually target the varieties from previous years which won’t necessarily match the predominant strain of current year. As a result, the efficiency of immunization rarely exceeds 70%. It is even lower in the subgroups of population such as older people who need this protection the most.
Existing anti-influenza drugs are not good enough
Since vaccines offer little protection, many pharmaceutical companies were attempted to develop proper drugs to treat flu. There was a certain degree of success here: drugs like Relenza and Tamiflu target biochemical pathways vital for the virus survival and help to cure the infection quickly. They have relatively broad spectrum due to the fact that they target the conservative enzymes present in all viruses. These enzymes change very little when virus mutates. As a result, drugs have broader activity across the viral strains than the vaccines. Unfortunately, the real efficiency of these drugs is difficult to evaluate since most relevant data still remain unpublished.
Still, prevention is better than cure, and development of effective vaccine is very desirable. In addition, the effective drugs are currently strictly regulated in attempt to avoid the emergence of viral resistance. Drugs like Tamiflu are believed to be the only relatively effective way of combating new types of influenza viruses such as avian flu variants that threatens to emerge and spread in the future. Nobody really knows how efficient the existing drugs will be against the future viral strains. This makes development of effective broad spectrum vaccine a priority.