Flu is one of the common respiratory illnesses caused by influenza viruses that can sometimes spread to the lungs as well as the nose and throat. Generally, it occurs as a mild disease but sometimes it may progress to severe disease, and in severe cases may cause even death. Taking a vaccine for the flu every year is the best approach to preventing the virus.
The majority of specialists concur that flu viruses are mostly conveyed by the tiny droplets produced when sick people cough, sneeze or talk. People close may catch these droplets in their mouths or noses. Less frequently, someone can contract the flu by contacting anything or a surface that has the virus and then touching their mouth, or nose.
Symptoms of influenza
There can be mild to severe illnesses caused by Influenza (flu), and at times can be fatal also. Flu symptoms usually come on suddenly. People who are suffering from flu may have some or all of these symptoms
- fever or feeling feverish/chills
- cough
- sore throat
- runny or stuffy nose
- muscle or body aches
- headaches
- fatigue (tiredness)
- Some people may have vomiting and diarrhoea, though this is more common in children than adults.
A step closer to a vaccination
When they isolated and recognized the influenza virus in 1933, British scientists Wilson Smith, C.H. Andrewes, and P.P. Laidlaw of London’s National Institute for Medical Research (NIMR) made a significant discovery. They determined that the illness was brought on by a virus when they examined the throat washings of influenza sufferers and found no microorganisms there.
Thomas Francis and Jonas Salk of the University of Michigan created the first inactivated flu vaccine with assistance from the US Army. Before being approved for widespread use in 1945, the vaccine was tested on the US military for both safety and efficacy.
Various strains
Because some influenza patients’ blood could not produce antibodies to the strain discovered in 1933, researchers had long assumed that multiple forms of influenza viruses existed. Scientists also identified influenza B, a different strain of the virus, throughout the testing period.
A brand-new bivalent vaccination that offered defence against both the H1N1 strain of influenza A and the recently identified influenza B virus was created in 1942.
Researchers learned that the then-current flu viruses were resistant to the vaccines in use during the 1947 flu season. The World Health Organization (WHO) established the Worldwide Influenza Centre in 1948 and the Global Influenza Surveillance and Response System (GISRS) in 1952 to study the viruses in circulation.
Ongoing efforts
To stay one step ahead of the viruses, researchers are continually attempting to develop new vaccine technologies.
Because influenza strains are constantly evolving, the seasonal flu vaccine often changes every year. The three influenza strains that each season’s vaccination is typically intended to protect against are two “A” strains and one “B” strain. The development process for the seasonal flu vaccination can take up to eight months from beginning to end—from choosing which three strains to target with the vaccine to producing the finished product.
A vaccine using recombinant DNA technology was approved in 2013, and further influenza vaccines based on newer technologies are currently being studied in clinical studies. A live attenuated vaccine administered as a nasal spray was initially licensed in 2003.
Despite these efforts, seasonal flu still claims the lives of up to 650 000 people annually throughout the world. Since influenza is a virus that is continually changing, immunity to one strain acquired through infection or vaccination may not always offer protection from newly emerging strains. We should be as ready as we can be when another flu pandemic strikes because we know from experience that it is likely to happen.
