Coronavirus disease (COVID-19) also known as 2019-nCov, 2019 Novel Coronavirus.
Understanding The Flu
Once you have had the measles you never get it again. But after you have had the flu, you can still get it next year, and the year after, and the year after that.
Once someone has had smallpox, if they survive, they never get it again. These are trite facts that everyone knows. Behind them is the key to the quest for an effective flu vaccine.
The flu virus, like other viruses, consists of genes at its center and protein molecules around its perimeter. The chemical makeup of the genes provides a code that determines the make-up of the protein molecules.
The proteins enable the virus to enter cells, killing them. Hence the illness. Sometimes the virus kills enough cells to cause bleeding in key parts of the body, and ultimately death.
When a virus enters the body, it is met by antibodies. To be effective, the antibodies have to combine with the protein molecules, making them unable to do their nasty work of entering and killing body cells. At first, the antibodies have the wrong make-up to do this, but they quickly adapt and become capable of linking with the proteins, neutralizing them.
Once the protein molecules are neutralized the virus can no longer continue existence. Finally, all the viruses are killed off and no longer attack the body cells. The patient gets well.
The slower the body is in producing the right type of antibodies in the right quantities, the more cells the virus can kill and the sicker the patient gets. If the body fails to produce enough antibodies of the right sort to wipe out the virus, the virus goes on killing body cells and the patient dies.
Once antibodies have been produced, they stay in the system. Next time the virus (the measles virus, for example) enters the body, the antibodies are ready. They multiply quickly and pounce upon the virus, killing it before it has a chance to enter and kill cells.
The flu virus is different. Its genes are more versatile than the genes of the measles, polio or smallpox virus. From time to time they mutate. Their codes change and the messages they send to the proteins change. As a result, the proteins on the perimeter of the virus change.
The antibodies are now temporarily stumped. They can no longer combine with the proteins, so the proteins can continue their sinister work of enabling the virus to enter cells, killing them and causing the patient to cough, ache, weaken and even catch pneumonia and die.
If the protein has changed only a little, the antibodies can adapt quite soon; but if the protein changes dramatically and quickly, the antibodies have an uphill fight. Individuals are less successful in combating the virus, and an epidemic breaks out.
Vaccines have been made for many viral diseases. They work by injecting dead or weakened viruses into the body, which then develops antibodies that can wipe out the real thing when it comes along.
The trouble with flu viruses is that they keep changing. A vaccine against one sort will be useless against the next, just as immunity built up from contracting one type of flu is of no value against next winter’s flu.
Original Antigenic Sin
Another trouble is that the new virus is very clever. It can trick the body into making antibodies that are only effective against the old virus. The scientists call it original antigenic sin.
Maybe the Calvinists among the researchers believe it predestined that there will never be a vaccine, and wretched humans will always suffer from the flu. Original antigenic sin means that, even if a vaccine is made anticipating the new strain, it will only generate antibodies effective against the old strain.
The third problem with flu vaccines is that the weakened virus injected into the body has a tendency to turn nasty and infect the very people the medicos want to be protected.
The first step is to determine the exact chemical nature of the flu viruses.
The second step is to compare the makeup of several different flu viruses. There are thousands of flu viruses, many of which the scientists have given peculiar names.
Here are some samples from the Bulletin of the World Health Organisation:
- A/Hong Kong/68
- Coronavirus (COVID-19)
The third step is to identify the stable parts of flu viruses. This step is being worked on now. The problem is that there may not be any stable parts.
The whole virus might change. If this is the case the quest for a new vaccine will have to take a new direction.
Part of the research involves recombinant DNA technology. The idea is to artificially, and in a controlled environment, change the gene. Then the resultant changes in the protein can be monitored. The study of artificial changes will result in knowledge of natural changes in the flu virus. This knowledge can help identify the stable parts of the virus.
If stable parts are found, the fourth step will be to make a vaccine that will cause the body to make antibodies that will attack those stable parts. This will mean that one vaccine will be effective against all flu viruses, no matter how many times they mutate.