Prof. Shima Gyoh
If you have been following my posts on vaccine production, you would be familiar with the earlier methods used in the history of vaccination. You would also know what I have referred to as the genetic engineering methods. One of the most advanced has been used for the first time, bypassing the longer stages of the others in our hurry to control the pandemic. This method uses “messenger-Ribo-Nucleic-Acid, or mRNA for short. Here are the basic principles.
If you want to build a house, you must first make a mould for your bricks. If you want to use big bricks, you make a big mould, if small bricks, then a small mould. If you need a decorative wall at the front, you make a mould for the decorative bricks. Moulds enable rapid production of many bricks of the same size, shape and design. No matter how elaborate the decorative brick might be, once you’ve got its mould, anyone who can mix concrete will produce the bricks very accurately, anywhere, any time!
Proteins constitute the walls of the house, and mRNA is the mould. There are thus different types of mRNA for producing different types of protein. Pfizer and Moderna used the mould (mRNA) SARS-CoV-2 uses to produce its Spike Protein (SP), the spear it uses to pierce and enter a human cell during infection. Inject this mould into the human cell, and cell will also produce the SP accurately, anywhere, any time!
Even though SP is produced within the human body, the body’s immune defence still recognises it as hostile unwanted material and attacks it, using the products of its digestion as a template to produce accurate neutralising compounds we call antibodies against the SP. If therefore, a greedy, hungry and wild corona virus comes calling, lands on a cell and tries piercing it with its Spike Protein, the antibodies against the SP blunt and twist the spear into a useless tangle, killing the virus. Mind you, the brave cell also dies, but only these two combatants are lost.
If this did not happen, the virus would enter the cell and its mRNA would cause the body cell to produce thousands of baby viruses, each with an SP. They would rupture the cell and emerge only to enter thousands of new body cells. This process is repeated, resulting in an exponential multiplication of the virus, with corresponding exponential slaughter of hundreds, thousands and millions of human body cells. War! It often causes the body to understandably panic! The survival siren is sounded, the body pours out profuse defensive hormones (cytokine storm), resulting in mass production of immune cells and a lot of blood and fluid to flood the area of infection, the only way the body knows how to take defence soldiers and their weapons to the war front. In the respiratory system, however, it results in the flooding of the lungs, obstructing the exchange of gases so necessary for life, and the patient tends to drown in his own body fluids. This is a dangerous obstruction to breathing called severe acute respiratory distress syndrome.
It therefore makes sense to inject the “mould” into body cells to produce the SP, when it automatically attracts the making of antibodies against it. This is how Pfizer and Moderna have used “genetic engineering” to produce their vaccines. But financial and political exigencies have forced the companies to rush and announce their products TOO SOON. Both products need further development before they can be more conveniently deployed.
Comparing the two vaccines, the Pfizer product, requiring storage at minus 70 degrees Centigrade would be difficult to administer in rural areas, as no ordinary refrigerator can attain that temperature. One deep freezer of that quality would cost about 4 million naira! Even glass containers disintegrate at those extra low temperatures, and special very tough glass has to be manufactured to contain the vaccine. On the other hand, the Moderna product would be easier to handle because it requires storage at only minus 20 degrees Centigrade. This temperature is within the scope of cheaper deep freezers and ordinary glass containers. I have little doubt that both companies would further develop their products to retain potency under more user-friendly conditions.
Remember that neither vaccine has reached the stage of formal approval, though both may receive Emergency Use Authorisation. Even then, they are more likely to become available to the public in developed countries during the second, more probably the third quarter of 2021. Unless there are drastic changes in circumstances, we are unlikely to have these vaccine in developing countries by the end of next year.
When the vaccine does eventually arrive our shores, we should follow the professional recommendations about who gets it first. Frontline clinical staff fighting the pandemic in hospitals and nursing homes should be the first receive it. Included on the priority list are the vulnerable, defined as those with chronic respiratory and cardiovascular diseases, the elderly above 60. In Nigeria, I would not be surprised if the political and financial heavyweights grab priority for themselves even above the clinical staff attending COVID-19 patients.
The public health specialists have stressed that, for MAXIMUM clinical benefits to society, we MUST use the vaccines WITHOUT dropping the already familiar precautions of prevention: continuing the use of masks, hand sanitation, social distancing, avoiding crowds and indoor events. Administrative authorities must continue to trace contacts and quarantine those exposed to infection, even if they have had it before, or have already been vaccinated, until we fill the present huge gaps in the epidemiology and clinical facts about the disease. We must also remember that none of the vaccines has 100% efficacy, meaning that vaccination does not guarantee immunity or the inability to be a symptomless carrier. Where it produces reasonable antibodies, we are not even sure of the effectiveness and duration of immunity, if any! We must continue to use all the arsenals we have against this pandemic until our knowledge advances sufficiently to bottle the infection.
We also face an ethical dilemma of how to deal with the superstition surrounding vaccination. Some of it is bound with religion, making it particularly difficult. While every person has the right to refuse vaccination, such refusal in this case could maintain a reservoir of infection that would continue to initiate epidemics, suffering and loss of lives. The question is, should society tolerate the individual’s right to refuse vaccination under these circumstances? My legal friend used to tell me that I had every right to swing my fist in all directions in the entire universe, but that right sharply ended where his nose began!