Universal Vaccine For Influenza Might Be Not So Far Away

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 Unfortunately, the real efficiency of these drugs is difficult to evaluate since most relevant data still remain unpublished.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.

Novel Approach Offers Hope Of Finding A Broad Spectrum Vaccine Against Flu

There were many attempts to develop a broad spectrum vaccine capable of preventing flu. Most of them, unfortunately, didn’t bring the desirable result. However, the results of new study recently published in Nature give hope that such a vaccine is likely to be available soon.

Researchers from pharmaceutical giant Sanofi have found one very conservative region in the influenza virus structure. It is located in the spikes that stick out of the virions surface and are made of specific viral protein called hemagglutinin. Since this particular part of virus is very conservative, it stays pretty much the same in all viral strains. Any changes of this part of hemagglutinin protein disable virus from interacting with human epithelial cells and infecting them. This is a reason why this conservative region stays practically unchanged across the variety of viral strains even though many other parts of virus can and do change dramatically, often beyond recognition.

New vaccine is capable of protecting against most flu strains recorded in more than 70 years

Researchers have developed a vaccine that recognizes and targets this particular region. Recognition of virus by vaccine triggers the adequate immune response and provides protection from infection. In the early experiments, new vaccine worked very well. It provided protection against many strains of the virus that were observed worldwide during 73 years between 1934 and 2007.

Despite these encouraging findings, scientists warn that new vaccine still have limitations. It works well only for viruses that have a particular type of hemagglutinin called H1. Most strains of seasonal flue belong to this group, but other potentially threatening versions of influenza such as avian flu have a different hemagglutinin type. Therefore, new vaccine is unlikely to protect from them. Nevertheless, protecting against the majority of common influenza strains is already a big step in the right direction. More work need to be done to develop vaccines against other forms of the virus.

How soon new vaccine will become available?

What we can reasonably expect in the near future as a result of this development? Testing of every new drug and medical treatment takes time but vaccines are usually developed faster than drugs. If safety tests are successful, the vaccine will be available in the next few years. This vaccine will be different from others: due to its broader spectrum, there will be no need to do vaccination every year. The vaccine is likely to work for several years and successfully combat the future seasonal varieties of influenza.