PAN – INFLUENZA VACCINE, IS IT POSSIBLE?
The idea to produce a universal pan – influenza vaccine that could protect us from any kind of influenza (Flu) viruses and their mutated variants, so that we don’t have to have a yearly flu shot, was conceived by research scientists in the year 2008.
A group of researchers, while working on blood samples obtained from people who have recovered from the flu, detected something unexpected and surprising- the presence of neutralizing antibodies in some blood samples against two subtypes of influenza spikes proteins. Further studies revealed that these neutralizing antibodies were bound to the stalk protein of the spike, instead of the HA head proteins. This was not supposed to happen.
To better understand why this is not supposed to happen, we must refresh the limited layman knowledge about the biology, structure and infectivity of influenza viruses.
As I have mentioned before, all viruses are “genetic parasites,” meaning that they are not complete cells. They cannot replicate themselves without infecting a host cell and using host cells’ genetic mechanisms to replicate.
Viruses could live harmlessly or symbiotically in any living species, including many animals or human hosts. But viruses could jump from an animal host to human host and become very infectious and dangerous. This is something that has been seen in the past and we are facing at the present time.
Novel influenza respiratory viruses that leaped from birds or pigs to people have caused four deadly pandemics in the last century. The deadliest one was named the Spanish Flu, which occurred in 1918, and is believed infected hundreds of millions of people and to have killed 50 million of them.
But eventually, when enough people got infected and survived the pandemic, “herd immunity” developed, the flu pandemic faded away and became seasonal flu.
Many scientists believe that the present coronavirus pandemic too will eventually become endemic and circulate, at a low level in the community, just like some corona viruses that cause the common cold.
However, the danger of seasonal flu should never be underestimated or belittled. The flu infects a billion people yearly, on a worldwide basis, and kills around 650,000 vulnerable people every year. Therefore, it is not wise to skip a yearly flu shot.
The main reason coronavirus and its variants can’t be eradicated has something to do with its structure, its ability to mutate frequently to change their structure, and the existence of a persistent vaccine hesitation in the community, and everyone not following the recommended protective measures.
The structure of influenza respiratory virus shows that its surface is studded with spike like proteins that contain a head and a short stalk. The head proteins (HA and NA) help the virus to bind to the host cells surface that they infect, whereas the stalk protein contains the genetic machinery of the virus which enable the virus to use the host cell’s DNA genetic mechanism to replicate.
Our immune system recognizes the head of spike proteins but not the stalk proteins as non- self (foreign) and reacts to it by producing neutralizing antibodies to destroy it. But the virus has an ability to change the head protein structure by frequent mutations, to form a new variant so that it can evade the developed immunity in the body either by vaccines or by old influenza infection.
One can’t help but wonder how the replicating mechanism of the virus knows how to replicate to in a way to evade the existing immunity? Does the replicating mechanism already able to use artificial intelligence (AI)?
That is why it’s impossible to eradicate influenza viruses. Every year, new flu vaccines must be made and injected to protect people from the flu.
On the other hand, the stalk protein which contain the replicating mechanism of the virus rarely changes with mutations, and our immune system doesn’t recognize it as non–self and doesn’t react to it. That is why the detection of anti- stalk protein neutralizing antibodies by researchers was so unexpected and gave them the idea that if they could develop a vaccine that is directed to the stalk protein, it will destroy viruses replicating mechanism and eradicate them.
The coronaviruses are respiratory viruses and, have similar structures and spontaneous ability to mutate, just like influenza viruses. Therefore, some researchers think that in coming decade, that scientists would be able to develop a pan–viral vaccine for both influenza and coronaviruses. Let’s hope and pray that they will succeed. In the meantime, we must continue taking yearly flu shots and I am afraid, yearly variant specific coronavirus shots as well.
