The Race for the Vaccine
Vaccination has proven effective in the prevention of infectious diseases throughout human history: it has led to the eradication of smallpox and has reduced the incidence of diseases with high mortality rates such as measles and rubella, among many others, to a minimum. There is no doubt that vaccines are an indispensable tool for the maintenance of public health. But what is a vaccine?
A vaccine is a pharmacological preparation designed to generate immunity, i.e. it stimulates our immune system so that it is able to generate the antibodies or defences necessary to fight a disease. This pharmacological preparation can be developed from a fragment of the infectious agent or be based on the use of the complete infectious agent, either inactivated or attenuated. For the covid-19 vaccine, and thanks to advances in molecular biology and genetic engineering, it has been possible to use a new technology: messenger ribonucleic acid (mRNA)
And what is mRNA? One of the dogmas of genetics and biology is that from the genetic material (DNA) an intermediate molecule is formed and the only mRNA is capable of understanding and expressing the information of our genetic material. This mRNA will be translated and will form a protein. Proteins are responsible for carrying out cellular functions and maintaining homeostasis and proper functioning of the individual.
The vaccines developed by Pfizer-BioNTech and Moderna are based on the use of mRNA which encodes a protein the virus is coated in. This mRNA is enveloped with a lipid substance that will allow it to enter our cells. Inside the cell it will release the mRNA and, using the cellular machinery, the viral coating protein can be synthesised. This protein will be recognised as a "foreign agent" to our body, which will activate the immune system to eliminate it. This first contact with this protein will allow the synthesis of the so-called "memory" antibodies, which will protect us against possible future infections with this virus. In other words, the vaccine will cause the virus to be neutralised before it can grow inside us and, therefore, we will neither develop the disease nor be transmitters, due to the decrease in the number of viruses in our body. The two vaccines have been shown to be effective, that is, they prevent the development of covid-19 in 95% and 94.1% of cases, respectively, and without causing significant side effects. In addition, Moderna recently published that its vaccine is effective with some of the new variants, such as the UK and South African vaccines. This is excellent news.
Even so, the two vaccines present unknowns to be solved. Among others, the duration of this immunity. But this does not make them unsafe or ineffective. In recent weeks there have been all kinds of careless claims about the effects of these vaccines which need to be refuted. For example, that they modify your genetic material, or that haste makes them unsafe. And I explain. It is impossible for this technology to modify genetic material: mRNA cannot be integrated into your genome, and therefore it will either produce the viral protein or it will be quickly eliminated. Nor have they been shown to be unsafe, as they have passed all validation protocols. Rather, they are a clear example of what can be achieved when both human and financial resources are available with a common goal.
Socially, the fact that it is a new technology is causing some suspicion. Some seem more favourable to the Oxford/AstraZeneca vaccine because it makes use of a previously tested technology. This vaccine uses mRNA encapsulated in a viral vector, which has been stripped of its pathogenic capacity, instead of its fatty coating. Even so, it is less effective (62%) than the two previous vaccines, but it is cheaper and can be stored more easily. The Oxford/AstraZeneca vaccine was not approved until Friday. Beyond the row over the delay in supply to European Union countries, it has been said that its use is not recommended the over 65s. The European Medicines Agency considers that it has been tested little in this population and that more tests are needed to recommend it for this group. This statement rather than worrying us should reassure us that regulatory agencies are not granting approval left, right and centre, but rather that the pressing need for vaccines is compromising efficiency and safety protocols.
What is relevant is that the scientific community is working to give us as many vaccines as possible. The more the better. We have to keep in mind that the entire world population has to be vaccinated. All vaccines are going through the rigour of the scientific method with the corresponding clinical trials. As a society we have to be prepared to get vaccinated once we receive permission from the health authorities. It is not enough to say that others should be vaccinated first. We need to reduce the circulation of the virus and this will only be achieved with the majority of the population vaccinated. It is a major challenge and solidarity should come first and without excuses. We trust in science and, above all, everyone should get vaccinated.
Núria Coll-Bonfill is a researcher at the Saint Louis University School of Medicine